diff --git a/rust2rpm/__main__.py b/rust2rpm/__main__.py
index 49023bd..0f575ad 100644
--- a/rust2rpm/__main__.py
+++ b/rust2rpm/__main__.py
@@ -426,7 +426,7 @@ def main():
 
     if args.suffix is not None:
         if metadata.name[-1].isdigit():
-            suffix = f'-{args.suffix}'
+            suffix = f'_{args.suffix}'
         else:
             suffix = args.suffix
     else: