diff --git a/CHANGELOG b/CHANGELOG
index d7b32927db..20041ba286 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,4 @@
+* Format timedelta in CSV export
 * Manage symbol widget
 * Fallback to model name as title
 * Manage deletable and writable state
diff --git a/tryton/gui/window/win_export.py b/tryton/gui/window/win_export.py
index 07ec4c6b65..ee967911b5 100644
--- a/tryton/gui/window/win_export.py
+++ b/tryton/gui/window/win_export.py
@@ -390,6 +390,11 @@ class WinExport(WinCSV):
                     val = val.strftime(common.date_format() + ' %X')
                 elif isinstance(val, datetime.date):
                     val = val.strftime(common.date_format())
+                elif isinstance(val, datetime.timedelta):
+                    val = common.timedelta.format(
+                        val, {'s': 1, 'm': 60, 'h': 60 * 60})
+            elif isinstance(val, datetime.timedelta):
+                val = val.total_seconds()
             elif isinstance(val, bool):
                 val = int(val)
             row.append(val)