diff --git a/pytorch_lightning/models/trainer.py b/pytorch_lightning/models/trainer.py
index eb4f63c1..ceb5e397 100644
--- a/pytorch_lightning/models/trainer.py
+++ b/pytorch_lightning/models/trainer.py
@@ -293,6 +293,7 @@ class Trainer(TrainerIO):
         """ This is called before pickling. """
         state = self.__dict__.copy()
         del state['cluster']
+        del state['experiment']
         return state
 
     def __dp_train(self, gpu_nb, proc_rank):