diff --git a/llmfoundry/utils/config_utils.py b/llmfoundry/utils/config_utils.py
index 2860b82059..f460da8344 100644
--- a/llmfoundry/utils/config_utils.py
+++ b/llmfoundry/utils/config_utils.py
@@ -276,6 +276,10 @@ def make_dataclass_and_log_config(
     dataclass_dict_config: DictConfig = om.structured(
         dataclass_constructor(**unstructured_config))
 
+    # Error on missing mandatory values:
+    for key in dataclass_fields:
+        _ = dataclass_dict_config[key]
+
     # Convert DictConfig to dict for dataclass constructor so that child
     # configs are not DictConfigs
     dataclass_config: T = dataclass_constructor(
diff --git a/scripts/train/train.py b/scripts/train/train.py
index 139f2ff7ff..19693852a2 100644
--- a/scripts/train/train.py
+++ b/scripts/train/train.py
@@ -44,10 +44,6 @@
 
 def validate_config(train_config: TrainConfig):
     """Validates compatible model and dataloader selection."""
-    # Check for missing mandatory fields and throw error early.
-    for field in TRAIN_CONFIG_KEYS:
-        _ = getattr(train_config, field)
-
     # Validate the rest of the config
     loaders = [train_config.train_loader]
     if train_config.eval_loaders is not None: