diff --git a/lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb b/lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb
index 6e5094f9d..c2391b88a 100644
--- a/lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb
+++ b/lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb
@@ -235,13 +235,13 @@ def case_insensitive
           self
         end
 
-        def allow_nil
-          @options[:allow_nil] = true
+        def allow_nil(allow_nil = true)
+          @options[:allow_nil] = allow_nil
           self
         end
 
-        def allow_blank
-          @options[:allow_blank] = true
+        def allow_blank(allow_blank = true)
+          @options[:allow_blank] = allow_blank
           self
         end