diff --git a/test/collections.js b/test/collections.js
index 6ffa5b59f..7e5ec6185 100644
--- a/test/collections.js
+++ b/test/collections.js
@@ -503,6 +503,19 @@
 
     deepEqual(_.sortBy(collection, 'x'), collection, 'sortBy accepts property string');
 
+    var collectionWithDifferentDatatypes = [
+      new Pair('1', 100), new Pair('1', 1),
+      new Pair('1', 2), new Pair('1', 200)
+    ];
+
+    var sortedList = _.sortBy(collectionWithDifferentDatatypes, function(pair) {
+      return [pair.x, pair.y];
+    });
+
+    var expectedSortedList = [new Pair('1', 1), new Pair('1', 2), new Pair('1', 100), new Pair('1', 200)];
+
+    deepEqual(sortedList, expectedSortedList, 'sortBy should sort it');
+
     list = ['q', 'w', 'e', 'r', 't', 'y'];
     deepEqual(_.sortBy(list), ['e', 'q', 'r', 't', 'w', 'y'], 'uses _.identity if iterator is not specified');
   });
diff --git a/underscore.js b/underscore.js
index a455456d2..55a74e7b3 100644
--- a/underscore.js
+++ b/underscore.js
@@ -347,6 +347,10 @@
       var a = left.criteria;
       var b = right.criteria;
       if (a !== b) {
+        for (var index = 0; index < _.keys(a).length; index++) {
+          if (a[index] > b[index] || a === void 0) return 1;
+          if (a[index] < b[index] || b === void 0) return -1;
+        }
         if (a > b || a === void 0) return 1;
         if (a < b || b === void 0) return -1;
       }