diff --git a/bwa.wdl b/bwa.wdl
index 4d9aad11729f1512143c5fdf1819854aad8323b4..b7762f29f0cb3ac870f9f55769b0752fa2e0cada 100644
--- a/bwa.wdl
+++ b/bwa.wdl
@@ -88,7 +88,8 @@ task mem {
         INPUT=/dev/stdin SORT_ORDER=coordinate OUTPUT=${outputFile}
     }
     output {
-        File alignedFile = select_first([outputFile])
+        File bamFile = select_first([outputFile])
+        File bamIndex = sub(bamFile, ".bam$", ".bai")
     }
     runtime {
         cpu: select_first([threads])