diff --git a/omg/mapedit.py b/omg/mapedit.py
index 3aea584..4eded0a 100644
--- a/omg/mapedit.py
+++ b/omg/mapedit.py
@@ -349,7 +349,7 @@ def to_lumps(self):
         m["_HEADER_"] = self.header
         m["VERTEXES"] = Lump(join([x.pack() for x in self.vertexes]))
         m["THINGS"  ] = Lump(join([x.pack() for x in self.things  ]))
-        m["LINEDEFS"] = Lump(join([x.pack() for x in linedefs     ]))
+        m["LINEDEFS"] = Lump(join([x.pack() for x in self.linedefs]))
         m["SIDEDEFS"] = Lump(join([x.pack() for x in self.sidedefs]))
         m["SECTORS" ] = Lump(join([x.pack() for x in self.sectors ]))
         m["NODES"]    = Lump(join([x.pack() for x in self.nodes   ]))