diff --git a/lib/config.js b/lib/config.js
index c353c1938..02cd8ec36 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -138,6 +138,12 @@ var normalizeConfig = function(config, configFilePath) {
     throw new Error('Invalid configuration: client.args must be an array of strings');
   }
 
+  var defaultClient = config.defaultClient || {};
+  Object.keys(defaultClient).forEach(function(key) {
+    var option = config.client[key];
+    config.client[key] = helper.isDefined(option) ? option : defaultClient[key];
+  });
+
   // normalize preprocessors
   var preprocessors = config.preprocessors || {};
   var normalizedPreprocessors = config.preprocessors = Object.create(null);
@@ -225,7 +231,7 @@ var Config = function() {
   this.loggers = [constant.CONSOLE_APPENDER];
   this.transports = ['websocket', 'flashsocket', 'xhr-polling', 'jsonp-polling'];
   this.plugins = ['karma-*'];
-  this.client = {
+  this.defaultClient = this.client = {
     args: [],
     useIframe: true,
     captureConsole: true
diff --git a/test/unit/config.spec.coffee b/test/unit/config.spec.coffee
index ca67a2e04..182561293 100644
--- a/test/unit/config.spec.coffee
+++ b/test/unit/config.spec.coffee
@@ -207,6 +207,22 @@ describe 'config', ->
       expect(config.basePath).to.equal resolveWinPath('./some')
       expect(config.urlRoot).to.equal '/' # default value
 
+    it 'should default unset options in client config', ->
+      config = e.parseConfig null, {client: {args: ['--test']}}
+
+      expect(config.client.useIframe).to.not.be.undefined
+      expect(config.client.captureConsole).to.not.be.undefined
+
+      config = e.parseConfig null, {client: {useIframe: true}}
+
+      expect(config.client.args).to.not.be.undefined
+      expect(config.client.captureConsole).to.not.be.undefined
+
+      config = e.parseConfig null, {client: {captureConsole: true}}
+
+      expect(config.client.useIframe).to.not.be.undefined
+      expect(config.client.args).to.not.be.undefined
+
 
   describe 'normalizeConfig', ->