diff --git a/product/ERP5OOo/Document/OOoDocument.py b/product/ERP5OOo/Document/OOoDocument.py
index 880cef6b6a91ffb5b61fb81e997ef2d631e644fb..44a4c79623d7d515d7ba5b7c96a2df0848dae5f9 100644
--- a/product/ERP5OOo/Document/OOoDocument.py
+++ b/product/ERP5OOo/Document/OOoDocument.py
@@ -309,7 +309,7 @@ class OOoDocument(PermanentURLMixIn, BaseConvertableAndFileMixin, File,
     """
     #XXX if document is empty, stop to try to convert.
     #XXX but I don't know what is a appropriate mime-type.(Yusei)
-    if self.get_size() == 0:
+    if not self.hasData():
       return 'text/plain', ''
     # if no conversion asked (format empty)
     # return raw data