diff --git a/umi-tools.wdl b/umi-tools.wdl
index db888603255a458f2baa3343756efae793f2f325..5e08e14d49fb188936e9cecc98e2dcd29daa2f38 100644
--- a/umi-tools.wdl
+++ b/umi-tools.wdl
@@ -78,7 +78,7 @@ task Dedup {
         File inputBam
         File inputBamIndex
         String outputBamPath
-        String tmpDir
+        String tmpDir = "./umiToolsDedupTmpDir"
 
         Boolean paired = true