diff --git a/product/CMFCategory/CategoryTool.py b/product/CMFCategory/CategoryTool.py
index 926f2f967d719819d4c261bf44ee54c5eab65409..675969df9fde8580bd1b4e9ee14ac05647009c0b 100755
--- a/product/CMFCategory/CategoryTool.py
+++ b/product/CMFCategory/CategoryTool.py
@@ -1348,8 +1348,11 @@ class CategoryTool( UniqueObject, Folder, Base ):
       This returns a catalog_search resource with can then be used by getCategoryMemberItemList
       """
       from Products.ERP5Form.Selection import DomainSelection
-      if base_category is None: 
-        raise CategoryError('getCategoryMemberValueList must know the base category')
+      if base_category is None:
+        if context.getPortalType() == "Base Category":
+          base_category = context.getBaseCategoryId()
+        else:
+          raise CategoryError('getCategoryMemberValueList must know the base category')
       strict_membership = kw.get('strict_membership', kw.get('strict', 0))
       catalog_search = self.portal_catalog(portal_type = portal_type,
                       # TODO: make it work in catalog tool