diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index dc5641805..06ad3ee22 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -140,6 +140,7 @@ int main( int argc, char *argv[] )
 
     if( fwrite( buf, 1, olen, f ) != olen )
     {
+        ret = 1;
         mbedtls_printf( "failed\n  ! fwrite failed\n\n" );
         fclose( f );
         goto exit;