diff --git a/fixed-data-table/fixed-data-table-tests.tsx b/fixed-data-table/fixed-data-table-tests.tsx
index a3b383dcc6..9265186fbd 100644
--- a/fixed-data-table/fixed-data-table-tests.tsx
+++ b/fixed-data-table/fixed-data-table-tests.tsx
@@ -11,7 +11,7 @@ var rows = [
     // .... and more
 ];
 
-function rowGetter(rowIndex) {
+function rowGetter(rowIndex: number) {
     return rows[rowIndex];
 }