diff --git a/apps/dgst.c b/apps/dgst.c
index a151fb845..5d5ab94ae 100644
--- a/apps/dgst.c
+++ b/apps/dgst.c
@@ -280,7 +280,7 @@ int MAIN(int argc, char **argv)
 		}
 		siglen = BIO_read(sigbio, sigbuf, siglen);
 		BIO_free(sigbio);
-		if(siglen <= 0) {
+		if(siglen == 0) {
 			BIO_printf(bio_err, "Error reading signature file %s\n",
 								sigfile);
 			ERR_print_errors(bio_err);