diff --git a/hydra-http-form.c b/hydra-http-form.c
index 92d5a9f..88f2e6b 100644
--- a/hydra-http-form.c
+++ b/hydra-http-form.c
@@ -582,6 +582,8 @@ char *html_encode(char *string) {
     ret = hydra_strrep(ret, "#", "%23");
   if (index(ret, '=') != NULL)
     ret = hydra_strrep(ret, "=", "%3D");
+  if (index(ret, '+') != NULL)
+    ret = hydra_strrep(ret, "+", "%2B");
 
   return ret;
 }