diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7e49a59c79f94..bb286e82759c7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -56,6 +56,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed metrics states being overridden in ddp mode ([#4482](https://github.com/PyTorchLightning/pytorch-lightning/pull/4482))
 
 
+- Fixed `lightning_getattr`, `lightning_hasattr` not finding the correct attributes in datamodule ([#4347](https://github.com/PyTorchLightning/pytorch-lightning/pull/4347))
+
+
 ## [1.0.5] - 2020-11-03
 
 ### Added
diff --git a/pytorch_lightning/utilities/parsing.py b/pytorch_lightning/utilities/parsing.py
index c8230205752d4..348eec110c3a1 100644
--- a/pytorch_lightning/utilities/parsing.py
+++ b/pytorch_lightning/utilities/parsing.py
@@ -177,8 +177,9 @@ def __repr__(self):
 def lightning_hasattr(model, attribute):
     """ Special hasattr for lightning. Checks for attribute in model namespace,
         the old hparams namespace/dict, and the datamodule. """
-    trainer = model.trainer
+    trainer = getattr(model, 'trainer', None)
 
+    attr = False
     # Check if attribute in model
     if hasattr(model, attribute):
         attr = True
@@ -189,10 +190,8 @@ def lightning_hasattr(model, attribute):
         else:
             attr = hasattr(model.hparams, attribute)
     # Check if the attribute in datamodule (datamodule gets registered in Trainer)
-    elif trainer is not None and trainer.datamodule is not None and hasattr(trainer.datamodule, attribute):
-        attr = getattr(trainer.datamodule, attribute)
-    else:
-        attr = False
+    if not attr and trainer is not None:
+        attr = hasattr(trainer.datamodule, attribute)
 
     return attr
 
@@ -200,18 +199,16 @@ def lightning_hasattr(model, attribute):
 def lightning_getattr(model, attribute):
     """ Special getattr for lightning. Checks for attribute in model namespace,
         the old hparams namespace/dict, and the datamodule. """
-    trainer = model.trainer
+    trainer = getattr(model, 'trainer', None)
 
     # Check if attribute in model
     if hasattr(model, attribute):
         attr = getattr(model, attribute)
     # Check if attribute in model.hparams, either namespace or dict
-    elif hasattr(model, 'hparams'):
-        if isinstance(model.hparams, dict):
-            attr = model.hparams[attribute]
-        else:
-            attr = getattr(model.hparams, attribute)
-
+    elif hasattr(model, 'hparams') and isinstance(model.hparams, dict) and attribute in model.hparams:
+        attr = model.hparams[attribute]
+    elif hasattr(model, 'hparams') and hasattr(model.hparams, attribute):
+        attr = getattr(model.hparams, attribute)
     # Check if the attribute in datamodule (datamodule gets registered in Trainer)
     elif trainer is not None and trainer.datamodule is not None and hasattr(trainer.datamodule, attribute):
         attr = getattr(trainer.datamodule, attribute)
@@ -230,7 +227,7 @@ def lightning_setattr(model, attribute, value):
         raise ValueError(f'{attribute} is neither stored in the model namespace'
                          ' nor the `hparams` namespace/dict, nor the datamodule.')
 
-    trainer = model.trainer
+    trainer = getattr(model, 'trainer', None)
 
     # Check if attribute in model
     if hasattr(model, attribute):
diff --git a/tests/utilities/parsing.py b/tests/utilities/parsing.py
index 13cfeaa64b01a..056590f1a6d35 100644
--- a/tests/utilities/parsing.py
+++ b/tests/utilities/parsing.py
@@ -24,6 +24,7 @@ class TestHparamsNamespace:
 
     class TestModel1:  # test for namespace
         learning_rate = 0
+
     model1 = TestModel1()
 
     class TestModel2:  # test for hparams namespace
@@ -41,12 +42,23 @@ class TestModel4:  # fail case
 
     model4 = TestModel4()
 
-    return model1, model2, model3, model4
+    class DataModule:
+        batch_size = 8
+
+    class Trainer:
+        datamodule = DataModule
+
+    class TestModel5:  # test for datamodule
+        trainer = Trainer
+
+    model5 = TestModel5()
+
+    return model1, model2, model3, model4, model5
 
 
 def test_lightning_hasattr(tmpdir):
     """ Test that the lightning_hasattr works in all cases"""
-    model1, model2, model3, model4 = _get_test_cases()
+    model1, model2, model3, model4, model5 = _get_test_cases()
     assert lightning_hasattr(model1, 'learning_rate'), \
         'lightning_hasattr failed to find namespace variable'
     assert lightning_hasattr(model2, 'learning_rate'), \
@@ -55,6 +67,8 @@ def test_lightning_hasattr(tmpdir):
         'lightning_hasattr failed to find hparams dict variable'
     assert not lightning_hasattr(model4, 'learning_rate'), \
         'lightning_hasattr found variable when it should not'
+    assert lightning_hasattr(model5, 'batch_size'), \
+        'lightning_hasattr failed to find batch_size in datamodule'
 
 
 def test_lightning_getattr(tmpdir):
@@ -64,6 +78,10 @@ def test_lightning_getattr(tmpdir):
         value = lightning_getattr(m, 'learning_rate')
         assert value == i, 'attribute not correctly extracted'
 
+    model5 = models[4]
+    assert lightning_getattr(model5, 'batch_size') == 8, \
+        'batch_size not correctly extracted'
+
 
 def test_lightning_setattr(tmpdir):
     """ Test that the lightning_setattr works in all cases"""
@@ -72,3 +90,8 @@ def test_lightning_setattr(tmpdir):
         lightning_setattr(m, 'learning_rate', 10)
         assert lightning_getattr(m, 'learning_rate') == 10, \
             'attribute not correctly set'
+
+    model5 = models[4]
+    lightning_setattr(model5, 'batch_size', 128)
+    assert lightning_getattr(model5, 'batch_size') == 128, \
+        'batch_size not correctly set'