diff --git a/docs/changes/newsfragments/214.enh b/docs/changes/newsfragments/214.enh
new file mode 100644
index 000000000..dcd629ae6
--- /dev/null
+++ b/docs/changes/newsfragments/214.enh
@@ -0,0 +1 @@
+Add missing ``abstractmethod`` decorators for ``get_valid_inputs`` methods of :class:`junifer.markers.BaseMarker` and :class:`junifer.preprocess.BasePreprocessor` by `Synchon Mandal`_
\ No newline at end of file
diff --git a/junifer/markers/base.py b/junifer/markers/base.py
index ba1c03da2..c78097c5d 100644
--- a/junifer/markers/base.py
+++ b/junifer/markers/base.py
@@ -45,6 +45,7 @@ class BaseMarker(ABC, PipelineStepMixin, UpdateMetaMixin):
             raise ValueError(f"{self.name} cannot be computed on {wrong_on}")
         self._on = on
 
+    @abstractmethod
     def get_valid_inputs(self) -> List[str]:
         """Get valid data types for input.
 
diff --git a/junifer/preprocess/base.py b/junifer/preprocess/base.py
index c9f8b97e9..2423cc251 100644
--- a/junifer/preprocess/base.py
+++ b/junifer/preprocess/base.py
@@ -79,6 +79,7 @@ class BasePreprocessor(ABC, PipelineStepMixin, UpdateMetaMixin):
             klass=NotImplementedError,
         )
 
+    @abstractmethod
     def get_valid_inputs(self) -> List[str]:
         """Get valid data types for input.