diff --git a/orte/test/mpi/ziatest.pl b/orte/test/mpi/ziatest.pl
index 17c5e335c2..877be628af 100755
--- a/orte/test/mpi/ziatest.pl
+++ b/orte/test/mpi/ziatest.pl
@@ -1,5 +1,5 @@
 #!/usr/bin/perl
 use Time::HiRes qw( gettimeofday );
 ($sec, $microsec) = gettimeofday;
-$cmd = "mpirun -n " . @ARGV[0] . " ./ziatest " . @ARGV[1] . " " . $sec . " " . $microsec;
+$cmd = "mpirun -npernode " . @ARGV[0] . " ./ziatest " . @ARGV[0] . " " . $sec . " " . $microsec;
 system($cmd);