diff --git a/lib/incoming_form.js b/lib/incoming_form.js
index 484d8d42..2a34f982 100644
--- a/lib/incoming_form.js
+++ b/lib/incoming_form.js
@@ -518,7 +518,7 @@ IncomingForm.prototype._uploadPath = function(filename) {
 
   if (this.keepExtensions) {
     var ext = path.extname(filename);
-    ext     = ext.replace(/(\.[a-z0-9]+).*/, '$1');
+    ext     = ext.replace(/(\.[a-z0-9]+).*/i, '$1');
 
     name += ext;
   }
diff --git a/test/unit/test-incoming-form.js b/test/unit/test-incoming-form.js
index 611fd3d2..e1b516d7 100644
--- a/test/unit/test-incoming-form.js
+++ b/test/unit/test-incoming-form.js
@@ -55,6 +55,9 @@ test('IncomingForm', {
 
     ext = path.extname(form._uploadPath('super.bar'));
     assert.equal(ext, '.bar');
+
+    ext = path.extname(form._uploadPath('file.aAa'));
+    assert.equal(ext, '.aAa');
   },
 });