diff --git a/lib/mongoid_paperclip.rb b/lib/mongoid_paperclip.rb
index 90787c5..d1690fa 100644
--- a/lib/mongoid_paperclip.rb
+++ b/lib/mongoid_paperclip.rb
@@ -108,7 +108,7 @@ def has_mongoid_attached_file(field, options = {})
         field(:"#{field}_file_name",    :type => String)
         field(:"#{field}_content_type", :type => String)
         field(:"#{field}_file_size",    :type => Integer)
-        field(:"#{field}_updated_at",   :type => DateTime)
+        field(:"#{field}_updated_at",   :type => Time)
         field(:"#{field}_fingerprint",  :type => String) unless disable_fingerprint
       end