diff --git a/biopet-framework/src/main/java/nl/lumc/sasc/biopet/wrappers/Star.scala b/biopet-framework/src/main/java/nl/lumc/sasc/biopet/wrappers/Star.scala
index 605ea9f5ea66811cc24e105d0655cf83b8885dba..f898b667606ffc6054abd37847762c31c0306fcf 100644
--- a/biopet-framework/src/main/java/nl/lumc/sasc/biopet/wrappers/Star.scala
+++ b/biopet-framework/src/main/java/nl/lumc/sasc/biopet/wrappers/Star.scala
@@ -43,7 +43,7 @@ class Star(private var globalConfig: Config) extends CommandLineFunction {
       cmd += required("--genomeDir", genomeDir) +
         required("--readFilesIn", R1) + optional(R2)
     }
-    cmd += optional("-runThreadN", nCoresRequest)
+    cmd += optional("--runThreadN", nCoresRequest)
     
     return cmd
   }