diff --git a/procps/kill.c b/procps/kill.c
index 9b31f28..c7a3c7f 100644
--- a/procps/kill.c
+++ b/procps/kill.c
@@ -140,7 +140,7 @@
 						if (kill(*pl, sig) != 0) {
 							errors++;
 							if (quiet==0)
-								perror_msg( "Could not kill pid '%d'", *pl);
+								perror_msg( "Could not kill pid '%ld'", *pl);
 						}
 					}
 			}