diff --git a/pppdump/pppdump.c b/pppdump/pppdump.c
index 87c2e8f1a..130300a17 100644
--- a/pppdump/pppdump.c
+++ b/pppdump/pppdump.c
@@ -320,7 +320,7 @@ dumpppp(f)
 			    ++r;
 			++r;
 			if (endp - r > mru)
-			    printf("     ERROR: length (%d) > MRU (%d)\n",
+			    printf("     ERROR: length (%zd) > MRU (%d)\n",
 				   endp - r, mru);
 			if (decompress && fcs == PPP_GOODFCS) {
 			    /* See if this is a CCP or compressed packet */