diff --git a/lib/tokenizer/Tokenizer.js b/lib/tokenizer/Tokenizer.js
index dbbbd3bf..21870e31 100644
--- a/lib/tokenizer/Tokenizer.js
+++ b/lib/tokenizer/Tokenizer.js
@@ -194,14 +194,15 @@ var Tokenizer = function(source, startOffset, startLine, startColumn) {
     this.lines = null;
     this.columns = null;
 
-    this.setSource(source || '', startOffset, startLine, startColumn);
+    this.setSource(source, startOffset, startLine, startColumn);
 };
 
 Tokenizer.prototype = {
     setSource: function(source, startOffset, startLine, startColumn) {
-        var start = firstCharOffset(source);
+        var safeSource = String(source || '');
+        var start = firstCharOffset(safeSource);
 
-        this.source = source;
+        this.source = safeSource;
         this.startOffset = typeof startOffset === 'undefined' ? 0 : startOffset;
         this.startLine = typeof startLine === 'undefined' ? 1 : startLine;
         this.startColumn = typeof startColumn === 'undefined' ? 1 : startColumn;
@@ -213,7 +214,7 @@ Tokenizer.prototype = {
         this.tokenStart = start;
         this.tokenEnd = start;
 
-        tokenLayout(this, source, start);
+        tokenLayout(this, safeSource, start);
         this.next();
     },
 
diff --git a/test/tokenizer.js b/test/tokenizer.js
index 7963e3f4..3ae192e6 100644
--- a/test/tokenizer.js
+++ b/test/tokenizer.js
@@ -39,6 +39,7 @@ describe('parser/tokenizer', function() {
 
         assert.equal(tokenizer.eof, true);
         assert.equal(tokenizer.tokenType, 0);
+        assert.equal(tokenizer.source, '');
     });
 
     it('edge case: empty input', function() {
@@ -46,6 +47,23 @@ describe('parser/tokenizer', function() {
 
         assert.equal(tokenizer.eof, true);
         assert.equal(tokenizer.tokenType, 0);
+        assert.equal(tokenizer.source, '');
+    });
+
+    it('should convert input to string', function() {
+        var tokenizer = new Tokenizer({
+            toString: function() {
+                return css;
+            }
+        });
+
+        assert.equal(tokenizer.source, css);
+    });
+
+    it('should accept a Buffer', function() {
+        var tokenizer = new Tokenizer(new Buffer(css));
+
+        assert.equal(tokenizer.source, css);
     });
 
     it('getTypes()', function() {