diff --git a/src/select-menu.js b/src/select-menu.js
index 91ee70f7e..c8c5bb1bf 100644
--- a/src/select-menu.js
+++ b/src/select-menu.js
@@ -113,7 +113,7 @@ dc.selectMenu = function (parent, chartGroup) {
         // check if only prompt option is selected
         if (values.length === 1 && values[0] === '') {
             values = null;
-        } else if (values.length === 1) {
+        } else if (!_multiple && values.length === 1) {
             values = values[0];
         }
         _chart.onChange(values);