diff --git a/app/models/repository.rb b/app/models/repository.rb
index 57a818270..c2736dd30 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -42,7 +42,7 @@ class Repository < ActiveRecord::Base
   validates_uniqueness_of :identifier, :scope => :project_id, :allow_blank => true
   validates_exclusion_of :identifier, :in => %w(show entry raw changes annotate diff show stats graph)
   # donwcase letters, digits, dashes, underscores but not digits only
-  validates_format_of :identifier, :with => /^[a-zA-Z0-9_\-]+$/, :allow_blank => true
+  validates_format_of :identifier, :with => /^[a-z0-9_\-]+$/, :allow_blank => true
   # Checks if the SCM is enabled when creating a repository
   validate :repo_create_validation, :on => :create