diff --git a/lib/authlogic/acts_as_authentic/login.rb b/lib/authlogic/acts_as_authentic/login.rb
index b518e344..a316da3c 100644
--- a/lib/authlogic/acts_as_authentic/login.rb
+++ b/lib/authlogic/acts_as_authentic/login.rb
@@ -118,7 +118,8 @@ def find_with_case(field, value, sensitivity = true)
             if sensitivity
               send("find_by_#{field}", value)
             else
-              where("LOWER(#{quoted_table_name}.#{field}) = ?", value.mb_chars.downcase).first
+              like_word = ::ActiveRecord::Base.connection.adapter_name == "PostgreSQL" ? "ILIKE" : "LIKE"
+              where("#{quoted_table_name}.#{field} #{like_word} ?", value.mb_chars).first
             end
           end
       end