diff --git a/lib/CSSStyleDeclaration.js b/lib/CSSStyleDeclaration.js
index 0a180f6..d7a7566 100644
--- a/lib/CSSStyleDeclaration.js
+++ b/lib/CSSStyleDeclaration.js
@@ -53,7 +53,9 @@ CSSStyleDeclaration.prototype = {
       this.removeProperty(name);
       return;
     }
-    var isCustomProperty = name.indexOf('--') === 0;
+    var isCustomProperty =
+      name.indexOf('--') === 0 ||
+      (typeof value === 'string' && /^var\(--[-\w]+,?.*\)$/.test(value));
     if (isCustomProperty) {
       this._setProperty(name, value, priority);
       return;
diff --git a/lib/parsers.js b/lib/parsers.js
index e0aa6e5..3c3b695 100644
--- a/lib/parsers.js
+++ b/lib/parsers.js
@@ -18,8 +18,7 @@ exports.TYPES = {
   ANGLE: 8,
   KEYWORD: 9,
   NULL_OR_EMPTY_STR: 10,
-  CALC: 11,
-  VAR: 12,
+  CALC: 11
 };
 
 // rough regular expressions
@@ -36,7 +35,6 @@ var colorRegEx4 =
   /^hsla?\(\s*(-?\d+|-?\d*.\d+)\s*,\s*(-?\d+|-?\d*.\d+)%\s*,\s*(-?\d+|-?\d*.\d+)%\s*(,\s*(-?\d+|-?\d*.\d+)\s*)?\)/;
 var calcRegEx = /^calc\((.*)\)$/;
 var angleRegEx = /^([-+]?[0-9]*\.?[0-9]+)(deg|grad|rad)$/;
-var varRegEx = /^var\((.*)\)$/;
 
 // This will return one of the above types based on the passed in string
 exports.valueType = function valueType(val) {
@@ -69,9 +67,6 @@ exports.valueType = function valueType(val) {
   if (calcRegEx.test(val)) {
     return exports.TYPES.CALC;
   }
-  if (varRegEx.test(val)) {
-    return exports.TYPES.VAR;
-  }
   if (stringRegEx.test(val)) {
     return exports.TYPES.STRING;
   }
@@ -214,7 +209,7 @@ exports.parsePercent = function parsePercent(val) {
 // either a length or a percent
 exports.parseMeasurement = function parseMeasurement(val) {
   var type = exports.valueType(val);
-  if (type === exports.TYPES.CALC || type === exports.TYPES.VAR) {
+  if (type === exports.TYPES.CALC) {
     return val;
   }
 
@@ -293,9 +288,6 @@ exports.parseString = function parseString(val) {
 
 exports.parseColor = function parseColor(val) {
   var type = exports.valueType(val);
-  if (type === exports.TYPES.VAR) {
-    return val;
-  }
   if (type === exports.TYPES.NULL_OR_EMPTY_STR) {
     return val;
   }
diff --git a/lib/parsers.test.js b/lib/parsers.test.js
index 7800978..a792e1e 100644
--- a/lib/parsers.test.js
+++ b/lib/parsers.test.js
@@ -91,21 +91,21 @@ describe('valueType', () => {
     let input = 'var(--foo)';
     let output = parsers.valueType(input);
 
-    expect(output).toEqual(parsers.TYPES.VAR);
+    expect(output).toEqual(parsers.TYPES.KEYWORD);
   });
 
   it('returns var from var(--foo, var(--bar))', () => {
     let input = 'var(--foo, var(--bar))';
     let output = parsers.valueType(input);
 
-    expect(output).toEqual(parsers.TYPES.VAR);
+    expect(output).toEqual(parsers.TYPES.KEYWORD);
   });
 
   it('returns var from var(--foo, calc(var(--bar) * 2))', () => {
     let input = 'var(--foo, calc(var(--bar) * 2))';
     let output = parsers.valueType(input);
 
-    expect(output).toEqual(parsers.TYPES.VAR);
+    expect(output).toEqual(parsers.TYPES.KEYWORD);
   });
 });
 describe('parseInteger', () => {
@@ -143,12 +143,11 @@ describe('parseColor', () => {
     expect(output).toEqual('rgba(5, 5, 5, 0.5)');
   });
 
-
   it('should pass through vars', () => {
     let input = 'var(--foo)';
     let output = parsers.valueType(input);
 
-    expect(output).toEqual(parsers.TYPES.VAR);
+    expect(output).toEqual(parsers.TYPES.KEYWORD);
   });
 
   it.each([