diff --git a/openapi_core/unmarshalling/schemas/unmarshallers.py b/openapi_core/unmarshalling/schemas/unmarshallers.py
index 53ddcc34..1df9ed09 100644
--- a/openapi_core/unmarshalling/schemas/unmarshallers.py
+++ b/openapi_core/unmarshalling/schemas/unmarshallers.py
@@ -137,6 +137,9 @@ def _unmarshal_properties(
 class MultiTypeUnmarshaller(PrimitiveUnmarshaller):
     def __call__(self, value: Any) -> Any:
         primitive_type = self.schema_validator.get_primitive_type(value)
+        # OpenAPI 3.0: handle no type for None
+        if primitive_type is None:
+            return None
         unmarshaller = self.schema_unmarshaller.get_type_unmarshaller(
             primitive_type
         )
@@ -247,6 +250,9 @@ def unmarshal(self, value: Any) -> Any:
         schema_type = self.schema.getkey("type")
         type_unmarshaller = self.get_type_unmarshaller(schema_type)
         typed = type_unmarshaller(value)
+        # skip finding format for None
+        if typed is None:
+            return None
         schema_format = self.find_format(value)
         if schema_format is None:
             return typed
diff --git a/openapi_core/validation/schemas/validators.py b/openapi_core/validation/schemas/validators.py
index c822a82f..7a764e31 100644
--- a/openapi_core/validation/schemas/validators.py
+++ b/openapi_core/validation/schemas/validators.py
@@ -94,6 +94,7 @@ def get_primitive_type(self, value: Any) -> Optional[str]:
                 continue
             assert isinstance(schema_type, (str, type(None)))
             return schema_type
+        # OpenAPI 3.0: None is not a primitive type so None value will not find any type
         return None
 
     def iter_valid_schemas(self, value: Any) -> Iterator[SchemaPath]:
diff --git a/tests/integration/unmarshalling/test_unmarshallers.py b/tests/integration/unmarshalling/test_unmarshallers.py
index 764fc3af..54e944a3 100644
--- a/tests/integration/unmarshalling/test_unmarshallers.py
+++ b/tests/integration/unmarshalling/test_unmarshallers.py
@@ -1840,6 +1840,25 @@ def test_object_property_nullable(self, unmarshallers_factory):
 
         assert result == value
 
+    def test_subschema_nullable(self, unmarshallers_factory):
+        schema = {
+            "oneOf": [
+                {
+                    "type": "integer",
+                },
+                {
+                    "nullable": True,
+                },
+            ]
+        }
+        spec = SchemaPath.from_dict(schema)
+        unmarshaller = unmarshallers_factory.create(spec)
+        value = None
+
+        result = unmarshaller.unmarshal(value)
+
+        assert result is None
+
 
 class TestOAS30RequestSchemaUnmarshallersFactory(
     BaseTestOASSchemaUnmarshallersFactoryCall,
@@ -2086,3 +2105,22 @@ def test_any_null(self, unmarshallers_factory):
         result = unmarshaller.unmarshal(None)
 
         assert result is None
+
+    def test_subschema_null(self, unmarshallers_factory):
+        schema = {
+            "oneOf": [
+                {
+                    "type": "integer",
+                },
+                {
+                    "type": "null",
+                },
+            ]
+        }
+        spec = SchemaPath.from_dict(schema)
+        unmarshaller = unmarshallers_factory.create(spec)
+        value = None
+
+        result = unmarshaller.unmarshal(value)
+
+        assert result is None