diff --git a/index.js b/index.js
index 344762b..2b3dd11 100755
--- a/index.js
+++ b/index.js
@@ -18,7 +18,7 @@ var defaults = {
 };
 
 module.exports = postcss.plugin('postcss-px-to-viewport', function (options) {
-
+  
   var opts = objectAssign({}, defaults, options);
   var pxReplace = createPxReplace(opts.viewportWidth, opts.minPixelValue, opts.unitPrecision, opts.viewportUnit);
 
diff --git a/spec/px-to-viewport.spec.js b/spec/px-to-viewport.spec.js
index 4b3f26e..eaaa21c 100644
--- a/spec/px-to-viewport.spec.js
+++ b/spec/px-to-viewport.spec.js
@@ -184,6 +184,38 @@ describe('mediaQuery', function () {
   });
 });
 
+describe('propList', function () {
+  it('should only replace properties in the prop list', function () {
+      var css = '.rule { font-size: 16px; margin: 16px; margin-left: 5px; padding: 5px; padding-right: 16px }';
+      var expected = '.rule { font-size: 5vw; margin: 5vw; margin-left: 5px; padding: 5px; padding-right: 5vw }';
+      var options = {
+          propList: ['*font*', 'margin*', '!margin-left', '*-right', 'pad']
+      };
+      var processed = postcss(pxToViewport(options)).process(css).css;
+
+      expect(processed).toBe(expected);
+  });
+
+  it('should only replace properties in the prop list with wildcard', function () {
+      var css = '.rule { font-size: 16px; margin: 16px; margin-left: 5px; padding: 5px; padding-right: 16px }';
+      var expected = '.rule { font-size: 16px; margin: 5vw; margin-left: 5px; padding: 5px; padding-right: 16px }';
+      var options = {
+          propList: ['*', '!margin-left', '!*padding*', '!font*']
+      };
+      var processed = postcss(pxToViewport(options)).process(css).css;
+
+      expect(processed).toBe(expected);
+  });
+
+  it('should replace all properties when prop list is not given', function () {
+      var rules = '.rule { margin: 16px; font-size: 15px }';
+      var expected = '.rule { margin: 5vw; font-size: 4.6875vw }';
+      var processed = postcss(pxToViewport()).process(rules).css;
+
+      expect(processed).toBe(expected);
+  });
+});
+
 describe('minPixelValue', function () {
   it('should not replace values below minPixelValue', function () {
       var options = {