diff --git a/pytorch_lightning/callbacks/model_checkpoint.py b/pytorch_lightning/callbacks/model_checkpoint.py
index cb0f36db44..ac73efd67c 100644
--- a/pytorch_lightning/callbacks/model_checkpoint.py
+++ b/pytorch_lightning/callbacks/model_checkpoint.py
@@ -41,7 +41,10 @@ warning_cache = WarningCache()
 
 class ModelCheckpoint(Callback):
     r"""
-    Save the model after every epoch by monitoring a quantity.
+    Save the model periodically by monitoring a quantity. Every metric logged with
+    :meth:`~pytorch_lightning.core.lightning.log` or :meth:`~pytorch_lightning.core.lightning.log_dict` in
+    LightningModule is a candidate for the monitor key. For more information, see
+    :ref:`weights_loading`.
 
     After training finishes, use :attr:`best_model_path` to retrieve the path to the
     best checkpoint file and :attr:`best_model_score` to retrieve its score.