diff --git a/lodash.js b/lodash.js
index 43d8d2d73..d61413c91 100644
--- a/lodash.js
+++ b/lodash.js
@@ -2397,11 +2397,12 @@
       }
       var index = -1,
           indexOf = getIndexOf(),
-          prereq = !isSorted && indexOf === baseIndexOf,
+          prereq = indexOf === baseIndexOf,
           isLarge = prereq && createCache && length >= 200,
           isCommon = prereq && !isLarge,
           result = [];
 
+      isSorted = prereq && isSorted;
       if (isLarge) {
         var seen = createCache();
         indexOf = cacheIndexOf;
diff --git a/test/test.js b/test/test.js
index b01b7685f..7d0cdafc2 100644
--- a/test/test.js
+++ b/test/test.js
@@ -4527,11 +4527,15 @@
       }
     });
 
-    test('`_.uniq` should work with a custom `_.indexOf` method', 2, function() {
+    test('`_.uniq` should work with a custom `_.indexOf` method', 6, function() {
       if (!isModularize) {
         _.indexOf = custom;
-        deepEqual(_.uniq(array), array.slice(0, 3));
-        deepEqual(_.uniq(largeArray), [largeArray[0]]);
+
+        _.each([false, true, _.identity], function(param) {
+          deepEqual(_.uniq(array, param), array.slice(0, 3));
+          deepEqual(_.uniq(largeArray, param), [largeArray[0]]);
+        });
+
         _.indexOf = indexOf;
       }
       else {