diff --git a/lib/url-join.js b/lib/url-join.js
index f81cdee..5574319 100644
--- a/lib/url-join.js
+++ b/lib/url-join.js
@@ -15,12 +15,13 @@
     if (strArray[0].match(/:\/*$/) && strArray.length > 1) {
       var first = strArray.shift();
       strArray[0] = first + strArray[0];
-      // There must be at least two in any, at most three slashes in the file protocol.
-      if (strArray[0].match(/file:\/\/\//)) {
-        strArray[0] = strArray[0].replace(/:\/*/, ':///');
-      } else {
-        strArray[0] = strArray[0].replace(/:\/*/, '://');
-      }
+    }
+
+    // There must be two or three slashes in the file protocol, two slashes in anything else.
+    if (strArray[0].match(/file:\/\/\//)) {
+      strArray[0] = strArray[0].replace(/:\/*/, ':///');
+    } else {
+      strArray[0] = strArray[0].replace(/:\/*/, '://');
     }
     
     for (var i = 0; i < strArray.length; i++) {
diff --git a/test/tests.js b/test/tests.js
index 818ed25..d6d732a 100644
--- a/test/tests.js
+++ b/test/tests.js
@@ -80,7 +80,7 @@ describe('url join', function () {
       .should.eql('http://www.google.com/foo/bar?test=123&boom=value&key=456');
 
     urljoin('http://example.org/x', '?a=1', '?b=2', '?c=3', '?d=4')
-    .should.eql('http://example.org/x?a=1&b=2&c=3&d=4');
+      .should.eql('http://example.org/x?a=1&b=2&c=3&d=4');
   });
 
   it('should merge slashes in paths correctly', function () {
@@ -92,4 +92,23 @@ describe('url join', function () {
     urljoin('http://example.org/', ':foo:', 'bar')
       .should.eql('http://example.org/:foo:/bar');
   });
+
+  it('should merge slashes in protocol correctly', function () {
+    urljoin('http://example.org', 'a')
+      .should.eql('http://example.org/a');
+    urljoin('http:', '//example.org', 'a')
+      .should.eql('http://example.org/a');
+    urljoin('http:///example.org', 'a')
+      .should.eql('http://example.org/a');
+    urljoin('file:///example.org', 'a')
+      .should.eql('file:///example.org/a');
+    urljoin('file:example.org', 'a')
+      .should.eql('file://example.org/a');
+    urljoin('file:/', 'example.org', 'a')
+      .should.eql('file://example.org/a');
+    urljoin('file:', '/example.org', 'a')
+      .should.eql('file://example.org/a');
+    urljoin('file:', '//example.org', 'a')
+      .should.eql('file://example.org/a');
+  });
 });