diff --git a/lib/connection-parameters.js b/lib/connection-parameters.js
index f31f28dd3..522c58943 100644
--- a/lib/connection-parameters.js
+++ b/lib/connection-parameters.js
@@ -52,6 +52,11 @@ var ConnectionParameters = function (config) {
 
   this.user = val('user', config)
   this.database = val('database', config)
+
+  if (this.database === undefined) {
+    this.database = this.user
+  }
+
   this.port = parseInt(val('port', config), 10)
   this.host = val('host', config)
   this.password = val('password', config)
diff --git a/lib/defaults.js b/lib/defaults.js
index 30214b1d8..e648af33c 100644
--- a/lib/defaults.js
+++ b/lib/defaults.js
@@ -15,7 +15,7 @@ module.exports = {
   user: process.platform === 'win32' ? process.env.USERNAME : process.env.USER,
 
   // name of database to connect
-  database: process.platform === 'win32' ? process.env.USERNAME : process.env.USER,
+  database: undefined,
 
   // database user's password
   password: null,
diff --git a/test/integration/client/configuration-tests.js b/test/integration/client/configuration-tests.js
index 87bb52d47..a6756ddee 100644
--- a/test/integration/client/configuration-tests.js
+++ b/test/integration/client/configuration-tests.js
@@ -14,7 +14,7 @@ for (var key in process.env) {
 suite.test('default values are used in new clients', function () {
   assert.same(pg.defaults, {
     user: process.env.USER,
-    database: process.env.USER,
+    database: undefined,
     password: null,
     port: 5432,
     rows: 0,
@@ -54,6 +54,28 @@ suite.test('modified values are passed to created clients', function () {
   })
 })
 
+suite.test('database defaults to user when user is non-default', () => {
+  {
+    pg.defaults.database = undefined
+
+    const client = new Client({
+      user: 'foo',
+    })
+
+    assert.strictEqual(client.database, 'foo')
+  }
+
+  {
+    pg.defaults.database = 'bar'
+
+    const client = new Client({
+      user: 'foo',
+    })
+
+    assert.strictEqual(client.database, 'bar')
+  }
+})
+
 suite.test('cleanup', () => {
   // restore process.env
   for (var key in realEnv) {
diff --git a/test/unit/connection-parameters/creation-tests.js b/test/unit/connection-parameters/creation-tests.js
index fc9f6521f..e19d5ad9f 100644
--- a/test/unit/connection-parameters/creation-tests.js
+++ b/test/unit/connection-parameters/creation-tests.js
@@ -16,8 +16,13 @@ test('ConnectionParameters construction', function () {
 })
 
 var compare = function (actual, expected, type) {
+  const expectedDatabase =
+    expected.database === undefined
+      ? expected.user
+      : expected.database
+
   assert.equal(actual.user, expected.user, type + ' user')
-  assert.equal(actual.database, expected.database, type + ' database')
+  assert.equal(actual.database, expectedDatabase, type + ' database')
   assert.equal(actual.port, expected.port, type + ' port')
   assert.equal(actual.host, expected.host, type + ' host')
   assert.equal(actual.password, expected.password, type + ' password')