diff --git a/wcs/sql.py b/wcs/sql.py
index 7d3252348..30260c8fc 100644
--- a/wcs/sql.py
+++ b/wcs/sql.py
@@ -836,9 +836,10 @@ class SqlMixin(object):
                 i += 1
             if field.store_structured_value:
                 value = row[i]
-                obdata['%s_structured' % field.id] = cPickle.loads(str(value))
-                if obdata['%s_structured' % field.id] is None:
-                    del obdata['%s_structured' % field.id]
+                if value is not None:
+                    obdata['%s_structured' % field.id] = cPickle.loads(str(value))
+                    if obdata['%s_structured' % field.id] is None:
+                        del obdata['%s_structured' % field.id]
                 i += 1
         return obdata
     _row2obdata = classmethod(_row2obdata)