diff --git a/lib/source-map/util.js b/lib/source-map/util.js
index 3bc13640..976f6cab 100644
--- a/lib/source-map/util.js
+++ b/lib/source-map/util.js
@@ -192,6 +192,10 @@ define(function (require, exports, module) {
    * @param aPath The path or URL to be made relative to aRoot.
    */
   function relative(aRoot, aPath) {
+    if (aRoot === "") {
+      aRoot = ".";
+    }
+
     aRoot = aRoot.replace(/\/$/, '');
 
     // XXX: It is possible to remove this block, and the tests still pass!
diff --git a/test/source-map/test-util.js b/test/source-map/test-util.js
index 44f7b7f6..997d1a26 100644
--- a/test/source-map/test-util.js
+++ b/test/source-map/test-util.js
@@ -203,6 +203,14 @@ define(function (require, exports, module) {
   exports['test relative()'] = function (assert, util) {
     assert.equal(libUtil.relative('/the/root', '/the/root/one.js'), 'one.js');
     assert.equal(libUtil.relative('/the/root', '/the/rootone.js'), '/the/rootone.js');
+
+    assert.equal(libUtil.relative('', '/the/root/one.js'), '/the/root/one.js');
+    assert.equal(libUtil.relative('.', '/the/root/one.js'), '/the/root/one.js');
+    assert.equal(libUtil.relative('', 'the/root/one.js'), 'the/root/one.js');
+    assert.equal(libUtil.relative('.', 'the/root/one.js'), 'the/root/one.js');
+
+    assert.equal(libUtil.relative('/', '/the/root/one.js'), 'the/root/one.js');
+    assert.equal(libUtil.relative('/', 'the/root/one.js'), 'the/root/one.js');
   };
 
 });