diff --git a/emmet-builders/emmet/builders/materials/oxidation_states.py b/emmet-builders/emmet/builders/materials/oxidation_states.py
new file mode 100644
index 0000000000..46a726e326
--- /dev/null
+++ b/emmet-builders/emmet/builders/materials/oxidation_states.py
@@ -0,0 +1,55 @@
+from typing import Dict, List, Optional
+
+from maggma.builders.map_builder import MapBuilder
+from maggma.core import Store
+from pymatgen.core import Structure
+
+from pymatgen.core import __version__ as pymatgen_version
+
+
+from emmet.core.oxidation_states import OxidationStateDoc
+
+
+class OxidationStates(MapBuilder):
+    def __init__(
+        self,
+        materials: Store,
+        oxidation_states: Store,
+        **kwargs,
+    ):
+        """
+        Creates Oxidation State documents from materials
+
+        Args:
+            materials: Store of materials docs
+            oxidation_states: Store to update with oxidation state document
+            query : query on materials to limit search
+        """
+        self.materials = materials
+        self.oxidation_states = oxidation_states
+        self.kwargs = kwargs
+
+        # Enforce that we key on material_id
+        self.materials.key = "material_id"
+        self.oxidation_states.key = "material_id"
+        super().__init__(
+            source=materials,
+            target=oxidation_states,
+            projection=["structure"],
+            **kwargs,
+        )
+
+    def unary_function(self, item):
+
+        structure = Structure.from_dict(item["structure"])
+        oxi_doc = OxidationStateDoc.from_structure(structure)
+        doc = oxi_doc.dict()
+
+        doc.update(
+            {
+                "pymatgen_version": pymatgen_version,
+                "successful": True,
+            }
+        )
+
+        return doc