diff --git a/lib/couchrest/mixins/extended_attachments.rb b/lib/couchrest/mixins/extended_attachments.rb
index 970f678..0f928bd 100644
--- a/lib/couchrest/mixins/extended_attachments.rb
+++ b/lib/couchrest/mixins/extended_attachments.rb
@@ -54,6 +54,7 @@ module CouchRest
       private
       
         def get_mime_type(path)
+          return nil if path.nil?
           type = ::MIME::Types.type_for(path)
           type.empty? ? nil : type.first.content_type
         end