diff --git a/lib/reporter.js b/lib/reporter.js
index 546571db6..5caedae04 100644
--- a/lib/reporter.js
+++ b/lib/reporter.js
@@ -9,6 +9,7 @@ var baseReporterDecoratorFactory = require('./reporters/base').decoratorFactory
 
 var createErrorFormatter = function (config, emitter, SourceMapConsumer) {
   var basePath = config.basePath
+  var urlRoot = config.urlRoot || ''
   var lastServedFiles = []
 
   emitter.on('file_list_modified', function (files) {
@@ -26,6 +27,7 @@ var createErrorFormatter = function (config, emitter, SourceMapConsumer) {
 
   var URL_REGEXP = new RegExp('(?:https?:\\/\\/' +
     config.hostname + '(?:\\:' + config.port + ')?' + ')?\\/?' +
+    urlRoot + '\\/?' +
     '(base/|absolute)' + // prefix, including slash for base/ to create relative paths.
     '((?:[A-z]\\:)?[^\\?\\s\\:]*)' + // path
     '(\\?\\w*)?' + // sha
diff --git a/test/unit/reporter.spec.js b/test/unit/reporter.spec.js
index cb8dd15c3..230817bd3 100644
--- a/test/unit/reporter.spec.js
+++ b/test/unit/reporter.spec.js
@@ -99,6 +99,11 @@ describe('reporter', () => {
       expect(formatError('at http://localhost:123/base/a.js?123')).to.equal('at a.js\n')
     })
 
+    it('should restore urlRoot paths', () => {
+      formatError = m.createErrorFormatter({ urlRoot: '/__karma__', basePath: '/some/base', hostname: 'localhost', port: 123 }, emitter)
+      expect(formatError('at http://localhost:123/__karma__/base/sub/a.js?123')).to.equal('at sub/a.js\n')
+    })
+
     it('should restore absolute paths', () => {
       var ERROR = 'at http://localhost:8080/absolute/usr/path.js?6e31cb249ee5b32d91f37ea516ca0f84bddc5aa9'
       expect(formatError(ERROR)).to.equal('at /usr/path.js\n')