diff --git a/CHANGELOG.md b/CHANGELOG.md
index f24d11f9065af..8e889029814c8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -185,6 +185,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Do not print top-k verbose log with `ModelCheckpoint(monitor=None)` ([#6109](https://github.com/PyTorchLightning/pytorch-lightning/pull/6109))
 
 
+- Fixed csv extension check ([#6436](https://github.com/PyTorchLightning/pytorch-lightning/pull/6436))
+
+
 - Fixed `ModelCheckpoint(monitor=None, save_last=True)` not saving checkpoints ([#6136](https://github.com/PyTorchLightning/pytorch-lightning/pull/6136))
 
 
diff --git a/pytorch_lightning/core/saving.py b/pytorch_lightning/core/saving.py
index 280eca55260a7..ffa9b0a1359ee 100644
--- a/pytorch_lightning/core/saving.py
+++ b/pytorch_lightning/core/saving.py
@@ -136,7 +136,7 @@ def load_from_checkpoint(
 
         if hparams_file is not None:
             extension = hparams_file.split('.')[-1]
-            if extension.lower() in ('csv'):
+            if extension.lower() == 'csv':
                 hparams = load_hparams_from_tags_csv(hparams_file)
             elif extension.lower() in ('yml', 'yaml'):
                 hparams = load_hparams_from_yaml(hparams_file)