diff --git a/core/python/Sample.py b/core/python/Sample.py
index 1b72d79..09bd03a 100644
--- a/core/python/Sample.py
+++ b/core/python/Sample.py
@@ -166,6 +166,7 @@ def combine(cls, name, samples, texName = None, maxN = None, color = 0):
 
         return cls(name = name, \
                    treeName = check_equal_([s.treeName for s in samples]),
+                   xSection = check_equal_([s.xSection for s in samples]),
                    normalization = normalization,
                    files = files,
                    selectionString = check_equal_([s.selectionString for s in samples]),