diff --git a/packages/core/integration-tests/test/css.js b/packages/core/integration-tests/test/css.js
index 422b8b9a01f..4203d105755 100644
--- a/packages/core/integration-tests/test/css.js
+++ b/packages/core/integration-tests/test/css.js
@@ -289,9 +289,9 @@ describe('css', function() {
     assert.equal(typeof output, 'function');
 
     let value = output();
-    assert(/_index_[0-9a-z]+_1/.test(value));
+    assert(/_index_[0-9a-z]/.test(value));
 
-    let cssClass = value.match(/(_index_[0-9a-z]+_1)/)[1];
+    let cssClass = value.match(/(_index_[0-9a-z]+)/)[1];
 
     let css = await fs.readFile(
       path.join(__dirname, '/dist/index.css'),
@@ -313,6 +313,207 @@ describe('css', function() {
     assert.equal(run1(), run2());
   });
 
+  it('should support postcss composes imports', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/postcss-composes/index.js')
+    );
+
+    await assertBundleTree(b, {
+      name: 'index.js',
+      assets: ['index.js', 'composes-1.css', 'composes-2.css', 'mixins.css'],
+      childBundles: [
+        {
+          name: 'index.css',
+          assets: ['composes-1.css', 'composes-2.css', 'mixins.css'],
+          childBundles: []
+        },
+        {
+          type: 'map'
+        }
+      ]
+    });
+
+    let output = await run(b);
+    assert.equal(typeof output, 'function');
+
+    let value = output();
+    const composes1Classes = value.composes1.split(' ');
+    const composes2Classes = value.composes2.split(' ');
+    assert(composes1Classes[0].startsWith('_composes1_'));
+    assert(composes1Classes[1].startsWith('_test_'));
+    assert(composes2Classes[0].startsWith('_composes2_'));
+    assert(composes2Classes[1].startsWith('_test_'));
+
+    let css = await fs.readFile(
+      path.join(__dirname, '/dist/index.css'),
+      'utf8'
+    );
+    let cssClass1 = value.composes1.match(/(_composes1_[0-9a-z]+)/)[1];
+    assert(css.includes(`.${cssClass1}`));
+    let cssClass2 = value.composes2.match(/(_composes2_[0-9a-z]+)/)[1];
+    assert(css.includes(`.${cssClass2}`));
+  });
+
+  it('should not include css twice for postcss composes imports', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/postcss-composes/index.js')
+    );
+
+    await run(b);
+
+    let css = await fs.readFile(
+      path.join(__dirname, '/dist/index.css'),
+      'utf8'
+    );
+    assert.equal(
+      css.indexOf('height: 100px;'),
+      css.lastIndexOf('height: 100px;')
+    );
+  });
+
+  it('should support postcss composes imports for sass', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/postcss-composes/index2.js')
+    );
+
+    await assertBundleTree(b, {
+      name: 'index2.js',
+      assets: ['index2.js', 'composes-3.css', 'mixins.scss'],
+      childBundles: [
+        {
+          name: 'index2.css',
+          assets: ['composes-3.css', 'mixins.scss'],
+          childBundles: []
+        },
+        {
+          type: 'map'
+        }
+      ]
+    });
+
+    let output = await run(b);
+    assert.equal(typeof output, 'function');
+
+    let value = output();
+    const composes3Classes = value.composes3.split(' ');
+    assert(composes3Classes[0].startsWith('_composes3_'));
+    assert(composes3Classes[1].startsWith('_test_'));
+
+    let css = await fs.readFile(
+      path.join(__dirname, '/dist/index2.css'),
+      'utf8'
+    );
+    assert(css.includes('height: 200px;'));
+  });
+
+  it('should support postcss composes imports with custom path names', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/postcss-composes/index3.js')
+    );
+
+    await assertBundleTree(b, {
+      name: 'index3.js',
+      assets: ['index3.js', 'composes-4.css', 'mixins.css'],
+      childBundles: [
+        {
+          name: 'index3.css',
+          assets: ['composes-4.css', 'mixins.css'],
+          childBundles: []
+        },
+        {
+          type: 'map'
+        }
+      ]
+    });
+
+    let output = await run(b);
+    assert.equal(typeof output, 'function');
+
+    let value = output();
+    const composes4Classes = value.composes4.split(' ');
+    assert(composes4Classes[0].startsWith('_composes4_'));
+    assert(composes4Classes[1].startsWith('_test_'));
+
+    let css = await fs.readFile(
+      path.join(__dirname, '/dist/index3.css'),
+      'utf8'
+    );
+    assert(css.includes('height: 100px;'));
+  });
+
+  it('should support deep nested postcss composes imports', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/postcss-composes/index4.js')
+    );
+
+    await assertBundleTree(b, {
+      name: 'index4.js',
+      assets: [
+        'index4.js',
+        'composes-5.css',
+        'mixins-intermediate.css',
+        'mixins.css'
+      ],
+      childBundles: [
+        {
+          name: 'index4.css',
+          assets: ['composes-5.css', 'mixins-intermediate.css', 'mixins.css'],
+          childBundles: []
+        },
+        {
+          type: 'map'
+        }
+      ]
+    });
+
+    let output = await run(b);
+    assert.equal(typeof output, 'function');
+
+    let value = output();
+    const composes5Classes = value.composes5.split(' ');
+    assert(composes5Classes[0].startsWith('_composes5_'));
+    assert(composes5Classes[1].startsWith('_intermediate_'));
+    assert(composes5Classes[2].startsWith('_test_'));
+
+    let css = await fs.readFile(
+      path.join(__dirname, '/dist/index4.css'),
+      'utf8'
+    );
+    assert(css.includes('height: 100px;'));
+    assert(css.includes('height: 300px;'));
+    assert(css.indexOf('._test_') < css.indexOf('._intermediate_'));
+  });
+
+  it('should support postcss composes imports for multiple selectors', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/postcss-composes/index5.js')
+    );
+
+    await assertBundleTree(b, {
+      name: 'index5.js',
+      assets: ['index5.js', 'composes-6.css', 'mixins.css'],
+      childBundles: [
+        {
+          name: 'index5.css',
+          assets: ['composes-6.css', 'mixins.css'],
+          childBundles: []
+        },
+        {
+          type: 'map'
+        }
+      ]
+    });
+
+    let output = await run(b);
+    assert.equal(typeof output, 'function');
+
+    let value = output();
+    const composes6Classes = value.composes6.split(' ');
+    assert(composes6Classes[0].startsWith('_composes6_'));
+    assert(composes6Classes[1].startsWith('_test_'));
+    assert(composes6Classes[2].startsWith('_test-2_'));
+  });
+
   it('should minify CSS in production mode', async function() {
     let b = await bundle(
       path.join(__dirname, '/integration/cssnano/index.js'),
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/.postcssrc b/packages/core/integration-tests/test/integration/postcss-composes/.postcssrc
new file mode 100644
index 00000000000..050061e1080
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/.postcssrc
@@ -0,0 +1,3 @@
+{
+  "modules": true
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/composes-1.css b/packages/core/integration-tests/test/integration/postcss-composes/composes-1.css
new file mode 100644
index 00000000000..547498770fc
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/composes-1.css
@@ -0,0 +1,4 @@
+.composes1 {
+  composes: test from './mixins.css';
+  border: 3px solid orange;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/composes-2.css b/packages/core/integration-tests/test/integration/postcss-composes/composes-2.css
new file mode 100644
index 00000000000..98163adf124
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/composes-2.css
@@ -0,0 +1,4 @@
+.composes2 {
+  composes: test from './mixins.css';
+  border: 3px solid red;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/composes-3.css b/packages/core/integration-tests/test/integration/postcss-composes/composes-3.css
new file mode 100644
index 00000000000..862fe412920
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/composes-3.css
@@ -0,0 +1,4 @@
+.composes3 {
+  composes: test from './mixins.scss';
+  border: 3px solid brown;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/composes-4.css b/packages/core/integration-tests/test/integration/postcss-composes/composes-4.css
new file mode 100644
index 00000000000..b0f3992251d
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/composes-4.css
@@ -0,0 +1,4 @@
+.composes4 {
+  composes: test from '~mixins.css';
+  border: 3px solid black;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/composes-5.css b/packages/core/integration-tests/test/integration/postcss-composes/composes-5.css
new file mode 100644
index 00000000000..4522e2bfdff
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/composes-5.css
@@ -0,0 +1,4 @@
+.composes5 {
+  composes: intermediate from './mixins-intermediate.css';
+  border: 3px solid yellow;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/composes-6.css b/packages/core/integration-tests/test/integration/postcss-composes/composes-6.css
new file mode 100644
index 00000000000..780d4fe80b0
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/composes-6.css
@@ -0,0 +1,4 @@
+.composes6 {
+  composes: test test-2 from './mixins.css';
+  border: 3px solid orangered;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/index.js b/packages/core/integration-tests/test/integration/postcss-composes/index.js
new file mode 100644
index 00000000000..19a9be12e73
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/index.js
@@ -0,0 +1,6 @@
+var map1 = require('./composes-1.css');
+var map2 = require('./composes-2.css');
+
+module.exports = function () {
+  return Object.assign({}, map1, map2);
+};
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/index2.js b/packages/core/integration-tests/test/integration/postcss-composes/index2.js
new file mode 100644
index 00000000000..b72aba8c409
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/index2.js
@@ -0,0 +1,5 @@
+var map3 = require('./composes-3.css');
+
+module.exports = function () {
+  return map3;
+};
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/index3.js b/packages/core/integration-tests/test/integration/postcss-composes/index3.js
new file mode 100644
index 00000000000..e1eb241f911
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/index3.js
@@ -0,0 +1,5 @@
+var map4 = require('./composes-4.css');
+
+module.exports = function () {
+  return map4;
+};
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/index4.js b/packages/core/integration-tests/test/integration/postcss-composes/index4.js
new file mode 100644
index 00000000000..315561cbd3b
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/index4.js
@@ -0,0 +1,5 @@
+var map5 = require('./composes-5.css');
+
+module.exports = function () {
+  return map5;
+};
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/index5.js b/packages/core/integration-tests/test/integration/postcss-composes/index5.js
new file mode 100644
index 00000000000..31932b14b88
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/index5.js
@@ -0,0 +1,5 @@
+var map6 = require('./composes-6.css');
+
+module.exports = function () {
+  return map6;
+};
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/mixins-intermediate.css b/packages/core/integration-tests/test/integration/postcss-composes/mixins-intermediate.css
new file mode 100644
index 00000000000..ebbbcafc863
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/mixins-intermediate.css
@@ -0,0 +1,4 @@
+.intermediate {
+  composes: test from './mixins.css';
+  height: 300px;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/mixins.css b/packages/core/integration-tests/test/integration/postcss-composes/mixins.css
new file mode 100644
index 00000000000..2de4a887869
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/mixins.css
@@ -0,0 +1,8 @@
+.test {
+  height: 100px;
+  width: 100px;
+}
+
+.test-2 {
+  background: red;
+}
diff --git a/packages/core/integration-tests/test/integration/postcss-composes/mixins.scss b/packages/core/integration-tests/test/integration/postcss-composes/mixins.scss
new file mode 100644
index 00000000000..6a801aa790a
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/postcss-composes/mixins.scss
@@ -0,0 +1,6 @@
+$test: 200px;
+
+.test {
+  height: $test;
+  width: $test;
+}
diff --git a/packages/core/integration-tests/test/less.js b/packages/core/integration-tests/test/less.js
index 11bc5ca177f..b8e3ca188d3 100644
--- a/packages/core/integration-tests/test/less.js
+++ b/packages/core/integration-tests/test/less.js
@@ -198,12 +198,12 @@ describe('less', function() {
 
     let output = await run(b);
     assert.equal(typeof output, 'function');
-    assert.equal(output(), '_index_ku5n8_1');
+    assert(output().startsWith('_index_'));
 
     let css = await fs.readFile(
       path.join(__dirname, '/dist/index.css'),
       'utf8'
     );
-    assert(css.includes('._index_ku5n8_1'));
+    assert(css.includes('._index_'));
   });
 });
diff --git a/packages/core/integration-tests/test/stylus.js b/packages/core/integration-tests/test/stylus.js
index f2dd3c087bc..34b6115ca0b 100644
--- a/packages/core/integration-tests/test/stylus.js
+++ b/packages/core/integration-tests/test/stylus.js
@@ -139,13 +139,13 @@ describe('stylus', function() {
 
     let output = await run(b);
     assert.equal(typeof output, 'function');
-    assert.equal(output(), '_index_g9mqo_1');
+    assert(output().startsWith('_index_'));
 
     let css = await fs.readFile(
       path.join(__dirname, '/dist/index.css'),
       'utf8'
     );
-    assert(css.includes('._index_g9mqo_1'));
+    assert(css.includes('._index_'));
   });
 
   it('should support requiring stylus files with glob dependencies', async function() {
diff --git a/packages/core/parcel-bundler/package.json b/packages/core/parcel-bundler/package.json
index 5fa76b6ed63..55b01ff9d9a 100644
--- a/packages/core/parcel-bundler/package.json
+++ b/packages/core/parcel-bundler/package.json
@@ -41,6 +41,7 @@
     "command-exists": "^1.2.6",
     "commander": "^2.11.0",
     "cross-spawn": "^6.0.4",
+    "css-modules-loader-core": "^1.1.0",
     "cssnano": "^4.0.0",
     "deasync": "^0.1.14",
     "dotenv": "^5.0.0",
diff --git a/packages/core/parcel-bundler/src/Asset.js b/packages/core/parcel-bundler/src/Asset.js
index 92b443a021b..adc2591ef3b 100644
--- a/packages/core/parcel-bundler/src/Asset.js
+++ b/packages/core/parcel-bundler/src/Asset.js
@@ -84,16 +84,7 @@ class Asset {
     this.dependencies.set(name, Object.assign({name}, opts));
   }
 
-  addURLDependency(url, from = this.name, opts) {
-    if (!url || isURL(url)) {
-      return url;
-    }
-
-    if (typeof from === 'object') {
-      opts = from;
-      from = this.name;
-    }
-
+  resolveDependency(url, from = this.name) {
     const parsed = URL.parse(url);
     let depName;
     let resolved;
@@ -110,8 +101,24 @@ class Asset {
       depName = './' + path.relative(path.dirname(this.name), resolved);
     }
 
+    return {depName, resolved};
+  }
+
+  addURLDependency(url, from = this.name, opts) {
+    if (!url || isURL(url)) {
+      return url;
+    }
+
+    if (typeof from === 'object') {
+      opts = from;
+      from = this.name;
+    }
+
+    const {depName, resolved} = this.resolveDependency(url, from);
+
     this.addDependency(depName, Object.assign({dynamic: true, resolved}, opts));
 
+    const parsed = URL.parse(url);
     parsed.pathname = this.options.parser
       .getAsset(resolved, this.options)
       .generateBundleName();
diff --git a/packages/core/parcel-bundler/src/assets/CSSAsset.js b/packages/core/parcel-bundler/src/assets/CSSAsset.js
index 8c3b7cde3fb..76cc0998ad5 100644
--- a/packages/core/parcel-bundler/src/assets/CSSAsset.js
+++ b/packages/core/parcel-bundler/src/assets/CSSAsset.js
@@ -6,6 +6,8 @@ const CssSyntaxError = require('postcss/lib/css-syntax-error');
 
 const URL_RE = /url\s*\("?(?![a-z]+:)/;
 const IMPORT_RE = /@import/;
+const COMPOSES_RE = /composes:.+from\s*("|').*("|')\s*;?/;
+const FROM_IMPORT_RE = /.+from\s*(?:"|')(.*)(?:"|')\s*;?/;
 const PROTOCOL_RE = /^[a-z]+:/;
 
 class CSSAsset extends Asset {
@@ -18,6 +20,7 @@ class CSSAsset extends Asset {
     return (
       !/\.css$/.test(this.name) ||
       IMPORT_RE.test(this.contents) ||
+      COMPOSES_RE.test(this.contents) ||
       URL_RE.test(this.contents)
     );
   }
@@ -90,6 +93,20 @@ class CSSAsset extends Asset {
           this.ast.dirty = true;
         }
       }
+
+      if (decl.prop === 'composes' && FROM_IMPORT_RE.test(decl.value)) {
+        let parsed = valueParser(decl.value);
+
+        parsed.walk(node => {
+          if (node.type === 'string') {
+            const [, importPath] = FROM_IMPORT_RE.exec(decl.value);
+            this.addURLDependency(importPath, {
+              dynamic: false,
+              loc: decl.source.start
+            });
+          }
+        });
+      }
     });
   }
 
diff --git a/packages/core/parcel-bundler/src/transforms/postcss.js b/packages/core/parcel-bundler/src/transforms/postcss.js
index a2626640d8d..0e209a3578a 100644
--- a/packages/core/parcel-bundler/src/transforms/postcss.js
+++ b/packages/core/parcel-bundler/src/transforms/postcss.js
@@ -1,7 +1,11 @@
 const localRequire = require('../utils/localRequire');
 const loadPlugins = require('../utils/loadPlugins');
+const md5 = require('../utils/md5');
 const postcss = require('postcss');
+const FileSystemLoader = require('css-modules-loader-core/lib/file-system-loader');
 const semver = require('semver');
+const path = require('path');
+const fs = require('@parcel/fs');
 
 module.exports = async function(asset) {
   let config = await getConfig(asset);
@@ -35,7 +39,10 @@ async function getConfig(asset) {
   }
 
   let postcssModulesConfig = {
-    getJSON: (filename, json) => (asset.cssModules = json)
+    getJSON: (filename, json) => (asset.cssModules = json),
+    Loader: createLoader(asset),
+    generateScopedName: (name, filename) =>
+      `_${name}_${md5(filename).substr(0, 5)}`
   };
 
   if (config.plugins && config.plugins['postcss-modules']) {
@@ -72,3 +79,31 @@ async function getConfig(asset) {
   config.to = asset.name;
   return config;
 }
+
+const createLoader = asset =>
+  class ParcelFileSystemLoader extends FileSystemLoader {
+    async fetch(composesPath, relativeTo) {
+      let importPath = composesPath.replace(/^["']|["']$/g, '');
+      const {resolved} = asset.resolveDependency(importPath, relativeTo);
+      let rootRelativePath = path.resolve(path.dirname(relativeTo), resolved);
+      const root = path.resolve('/');
+      // fixes an issue on windows which is part of the css-modules-loader-core
+      // see https://github.com/css-modules/css-modules-loader-core/issues/230
+      if (rootRelativePath.startsWith(root)) {
+        rootRelativePath = rootRelativePath.substr(root.length);
+      }
+
+      const source = await fs.readFile(resolved, 'utf-8');
+      const {exportTokens} = await this.core.load(
+        source,
+        rootRelativePath,
+        undefined,
+        this.fetch.bind(this)
+      );
+      return exportTokens;
+    }
+
+    get finalSource() {
+      return '';
+    }
+  };