diff --git a/CPAT.wdl b/CPAT.wdl
index afce53e2490841b57e1fcb0937279480058cbe07..972613cfdfa24806f98de88c2d48ce97ef81be7d 100644
--- a/CPAT.wdl
+++ b/CPAT.wdl
@@ -45,7 +45,7 @@ task CPAT {
     # to non-optionals.
     command {
         set -e
-        mkdir -p "$(dirname ~{outFilePath})"
+        mkdir -p "$(dirname ~{outputPrefix})"
         cpat.py \
         --gene ~{gene} \
         --outfile ~{outputPrefix} \