diff --git a/lib/authlogic/regex.rb b/lib/authlogic/regex.rb
index <HASH>..<HASH> 100644
--- a/lib/authlogic/regex.rb
+++ b/lib/authlogic/regex.rb
@@ -10,7 +10,7 @@ module Authlogic
     # for regular expressions.
     def self.email
       return @email_regex if @email_regex
-      email_name_regex  = '[A-Z0-9\.%\+\-]+'
+      email_name_regex  = '[A-Z0-9_\.%\+\-]+'
       domain_head_regex = '(?:[A-Z0-9\-]+\.)+'
       domain_tld_regex  = '(?:[A-Z]{2,4}|museum|travel)'
       @email_regex = /\A#{email_name_regex}@#{domain_head_regex}#{domain_tld_regex}\z/i
Add _ as allowed character in email, fixes change made last night