diff --git a/lib/color.js b/lib/color.js
index bb01518..4b6e6e6 100644
--- a/lib/color.js
+++ b/lib/color.js
@@ -2,24 +2,33 @@ var installedColorSpaces = [];
 var undef = function (obj) {
   return typeof obj === 'undefined';
 };
-var channelRegExp = /\s*(\.\d+|\d+(?:\.\d+)?)(%)?\s*/;
+var channelRegExp = /\s*(\.\d+|\d+(?:\.\d+)?)(%|deg)?\s*/;
 var percentageChannelRegExp = /\s*(\.\d+|100|\d?\d(?:\.\d+)?)%\s*/;
-var alphaChannelRegExp = /\s*(\.\d+|\d+(?:\.\d+)?)\s*/;
 var cssColorRegExp = new RegExp(
   '^(rgb|hsl|hsv)a?' +
     '\\(' +
     channelRegExp.source +
-    ',' +
+    '[, ]' +
     channelRegExp.source +
-    ',' +
+    '[, ]' +
+    channelRegExp.source +
+    '(?:[,/]' +
     channelRegExp.source +
-    '(?:,' +
-    alphaChannelRegExp.source +
     ')?' +
     '\\)$',
   'i'
 );
 
+function divisor(unit, channelNumber, hasHue) {
+  if (unit === '%') {
+    return 100;
+  } else if (unit === 'deg' || (hasHue && channelNumber === 0)) {
+    return 360;
+  } else if (!unit) {
+    return 255;
+  }
+}
+
 function color(obj) {
   if (Array.isArray(obj)) {
     if (typeof obj[0] === 'string' && typeof color[obj[0]] === 'function') {
@@ -46,37 +55,38 @@ function color(obj) {
     var matchCssSyntax = obj.match(cssColorRegExp);
     if (matchCssSyntax) {
       var colorSpaceName = matchCssSyntax[1].toUpperCase();
-      var alpha = undef(matchCssSyntax[8])
-        ? matchCssSyntax[8]
-        : parseFloat(matchCssSyntax[8]);
       var hasHue = colorSpaceName[0] === 'H';
-      var firstChannelDivisor = matchCssSyntax[3] ? 100 : hasHue ? 360 : 255;
-      var secondChannelDivisor = matchCssSyntax[5] || hasHue ? 100 : 255;
-      var thirdChannelDivisor = matchCssSyntax[7] || hasHue ? 100 : 255;
       if (undef(color[colorSpaceName])) {
         throw new Error('color.' + colorSpaceName + ' is not installed.');
       }
       return new color[colorSpaceName](
-        parseFloat(matchCssSyntax[2]) / firstChannelDivisor,
-        parseFloat(matchCssSyntax[4]) / secondChannelDivisor,
-        parseFloat(matchCssSyntax[6]) / thirdChannelDivisor,
-        alpha
+        parseFloat(matchCssSyntax[2]) / divisor(matchCssSyntax[3], 0, hasHue),
+        parseFloat(matchCssSyntax[4]) / divisor(matchCssSyntax[5], 1, hasHue),
+        parseFloat(matchCssSyntax[6]) / divisor(matchCssSyntax[7], 2, hasHue),
+        undef(matchCssSyntax[8])
+          ? matchCssSyntax[8]
+          : parseFloat(matchCssSyntax[8]) / (matchCssSyntax[9] ? 100 : 255)
       );
     }
     // Assume hex syntax
     if (obj.length < 6) {
       // Allow CSS shorthand
-      obj = obj.replace(/^#?([0-9a-f])([0-9a-f])([0-9a-f])$/i, '$1$1$2$2$3$3');
+      obj = obj.replace(
+        /^#?([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])?$/i,
+        '$1$1$2$2$3$3$4$4'
+      );
     }
-    // Split obj into red, green, and blue components
+    // Split obj into the red, green, blue, and optionally alpha component
     var hexMatch = obj.match(
-      /^#?([0-9a-f][0-9a-f])([0-9a-f][0-9a-f])([0-9a-f][0-9a-f])$/i
+      /^#?([0-9a-f][0-9a-f])([0-9a-f][0-9a-f])([0-9a-f][0-9a-f])([0-9a-f][0-9a-f])?$/i
     );
+
     if (hexMatch) {
       return new color.RGB(
         parseInt(hexMatch[1], 16) / 255,
         parseInt(hexMatch[2], 16) / 255,
-        parseInt(hexMatch[3], 16) / 255
+        parseInt(hexMatch[3], 16) / 255,
+        hexMatch[4] ? parseInt(hexMatch[4], 16) / 255 : 1
       );
     }
 
@@ -316,12 +326,7 @@ color.installColorSpace('RGB', ['red', 'green', 'blue', 'alpha'], {
 
   hexa: function () {
     var alphaString = Math.round(this._alpha * 255).toString(16);
-    return (
-      '#' +
-      '00'.substr(0, 2 - alphaString.length) +
-      alphaString +
-      this.hex().substr(1, 6)
-    );
+    return this.hex() + '00'.substr(0, 2 - alphaString.length) + alphaString;
   },
 
   css: function () {
diff --git a/test/parse.js b/test/parse.js
index d5305f2..fdcf9a7 100644
--- a/test/parse.js
+++ b/test/parse.js
@@ -53,4 +53,128 @@ describe('parsing', function () {
       expect(color('cmyk(100,100%,100%)'), 'to be false');
     });
   });
+
+  describe('with #rrggbbaa', function () {
+    var instance = color('#00ff0080');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#00ff00');
+    });
+
+    it('should have its alpha channel set correctly', function () {
+      expect(instance.alpha().toFixed(2), 'to equal', '0.50');
+    });
+  });
+
+  describe('with #rgba', function () {
+    var instance = color('#0f08');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#00ff00');
+    });
+
+    it('should have its alpha channel set correctly', function () {
+      expect(instance.alpha().toFixed(2), 'to equal', '0.53');
+    });
+  });
+
+  describe('with rgb(r, g, b)', function () {
+    var instance = color('rgb(10, 20, 30)');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#0a141e');
+    });
+  });
+
+  describe('with rgb(r,g,b)', function () {
+    var instance = color('rgb(10,20,30)');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#0a141e');
+    });
+  });
+
+  describe('with rgb(r g b)', function () {
+    var instance = color('rgb(10 20 30)');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#0a141e');
+    });
+  });
+
+  describe('with rgba(r g b / a)', function () {
+    var instance = color('rgba(10 20 30 / 50%)');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#0a141e');
+    });
+
+    it('should have its alpha channel set correctly', function () {
+      expect(instance.alpha().toFixed(2), 'to equal', '0.50');
+    });
+  });
+
+  describe('with rgba(r g b/a)', function () {
+    var instance = color('rgba(10 20 30/50%)');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#0a141e');
+    });
+
+    it('should have its alpha channel set correctly', function () {
+      expect(instance.alpha().toFixed(2), 'to equal', '0.50');
+    });
+  });
+
+  describe('with hsl(h s l) and the hue given as a percentage', function () {
+    var instance = color('hsl(10% 20% 30%)');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#5c503d');
+    });
+  });
+
+  describe('with hsl(h s l) and the hue given as an angle', function () {
+    var instance = color('hsl(10deg 20% 30%)');
+
+    it('should return a color instance', function () {
+      expect(instance, 'to be a color instance');
+    });
+
+    it('should be green', function () {
+      expect(instance.hex(), 'to equal', '#5c423d');
+    });
+  });
 });