diff --git a/src/lokijs.js b/src/lokijs.js
index 0588569c..2a02dacf 100644
--- a/src/lokijs.js
+++ b/src/lokijs.js
@@ -4050,12 +4050,17 @@
         };
       }
 
+      var data = [];
       //Run map function over each object in the resultset
       for (var j = 0; j < leftDataLength; j++) {
         key = leftKeyisFunction ? leftJoinKey(leftData[j]) : leftData[j][leftJoinKey];
-        result.push(mapFun(leftData[j], joinMap[key] || {}));
+        for( var k = 0; k < key.length; k++ )
+        {
+          data.push( joinMap[key[k]] );   
+        }
+        result.push(mapFun(leftData[j], data || {}));
+        data = [];
       }
-
       //return return a new resultset with no filters
       this.collection = new Collection('joinData');
       this.collection.insert(result);