diff --git a/app/helpers/queries_helper.rb b/app/helpers/queries_helper.rb
index d2991fd25..708a8acfb 100644
--- a/app/helpers/queries_helper.rb
+++ b/app/helpers/queries_helper.rb
@@ -309,7 +309,7 @@ module QueriesHelper
     else
       format_object(value, html: false) do |value|
         case value.class.name
-        when 'Float'
+        when 'Float', 'Rational'
           sprintf("%.2f", value).gsub('.', l(:general_csv_decimal_separator))
         when 'IssueRelation'
           value.to_s(object)
diff --git a/test/functional/timelog_controller_test.rb b/test/functional/timelog_controller_test.rb
index cd26f1b13..93b4c271b 100644
--- a/test/functional/timelog_controller_test.rb
+++ b/test/functional/timelog_controller_test.rb
@@ -1740,6 +1740,16 @@ class TimelogControllerTest < Redmine::ControllerTest
       get :index, :params => {:format => 'csv'}
       assert_response :success
       assert_equal 'text/csv; header=present', response.media_type
+
+      parsed_csv = CSV.parse(response.body)
+      assert_equal %w[Project Date User Activity Issue Comment Hours], parsed_csv.first
+      assert_equal(
+        [
+          'eCookbook', '03/12/2007', 'Redmine Admin', 'Design',
+          'Bug #1: Cannot print recipes', '', '150.00'
+        ],
+        parsed_csv.last
+      )
     end
   end