diff --git a/openapi_core/casting/schemas/casters.py b/openapi_core/casting/schemas/casters.py
index 048de19b..181d8813 100644
--- a/openapi_core/casting/schemas/casters.py
+++ b/openapi_core/casting/schemas/casters.py
@@ -1,7 +1,6 @@
 from __future__ import division
 
 from openapi_core.casting.schemas.exceptions import CastError
-from openapi_core.types import NoValue
 
 
 class PrimitiveCaster(object):
@@ -11,7 +10,7 @@ def __init__(self, schema, caster_callable):
         self.caster_callable = caster_callable
 
     def __call__(self, value):
-        if value in (None, NoValue):
+        if value is None:
             return value
         try:
             return self.caster_callable(value)
@@ -36,6 +35,6 @@ def items_caster(self):
         return self.casters_factory.create(self.schema / 'items')
 
     def __call__(self, value):
-        if value in (None, NoValue):
+        if value is None:
             return value
         return list(map(self.items_caster, value))
diff --git a/openapi_core/types.py b/openapi_core/types.py
deleted file mode 100644
index 8a8874d5..00000000
--- a/openapi_core/types.py
+++ /dev/null
@@ -1 +0,0 @@
-NoValue = object()
diff --git a/openapi_core/unmarshalling/schemas/unmarshallers.py b/openapi_core/unmarshalling/schemas/unmarshallers.py
index 2faf6165..a0e14cb9 100644
--- a/openapi_core/unmarshalling/schemas/unmarshallers.py
+++ b/openapi_core/unmarshalling/schemas/unmarshallers.py
@@ -14,7 +14,6 @@
 from openapi_core.schema.schemas import (
     get_all_properties, get_all_properties_names
 )
-from openapi_core.types import NoValue
 from openapi_core.unmarshalling.schemas.enums import UnmarshalContext
 from openapi_core.unmarshalling.schemas.exceptions import (
     UnmarshalError, ValidateError, InvalidSchemaValue,
@@ -38,9 +37,7 @@ def __init__(self, formatter, validator, schema):
         self.validator = validator
         self.schema = schema
 
-    def __call__(self, value=NoValue):
-        if value is NoValue:
-            value = self.schema.getkey('default')
+    def __call__(self, value):
         if value is None:
             return
 
@@ -145,7 +142,7 @@ class ArrayUnmarshaller(ComplexUnmarshaller):
     def items_unmarshaller(self):
         return self.unmarshallers_factory.create(self.schema / 'items')
 
-    def __call__(self, value=NoValue):
+    def __call__(self, value):
         value = super(ArrayUnmarshaller, self).__call__(value)
         if value is None and self.schema.getkey('nullable', False):
             return None
@@ -172,7 +169,7 @@ def unmarshal(self, value):
         else:
             return self._unmarshal_object(value)
 
-    def _unmarshal_object(self, value=NoValue):
+    def _unmarshal_object(self, value):
         if 'oneOf' in self.schema:
             properties = None
             for one_of_schema in self.schema / 'oneOf':
@@ -199,7 +196,7 @@ def _unmarshal_object(self, value=NoValue):
 
         return properties
 
-    def _unmarshal_properties(self, value=NoValue, one_of_schema=None):
+    def _unmarshal_properties(self, value, one_of_schema=None):
         all_props = get_all_properties(self.schema)
         all_props_names = get_all_properties_names(self.schema)
 
@@ -255,7 +252,7 @@ class AnyUnmarshaller(ComplexUnmarshaller):
         'integer', 'number', 'string',
     ]
 
-    def unmarshal(self, value=NoValue):
+    def unmarshal(self, value):
         one_of_schema = self._get_one_of_schema(value)
         if one_of_schema:
             return self.unmarshallers_factory.create(one_of_schema)(value)
diff --git a/tests/unit/unmarshalling/test_unmarshal.py b/tests/unit/unmarshalling/test_unmarshal.py
index 4b38d67f..f959de9d 100644
--- a/tests/unit/unmarshalling/test_unmarshal.py
+++ b/tests/unit/unmarshalling/test_unmarshal.py
@@ -5,7 +5,6 @@
 import pytest
 
 from openapi_core.spec.paths import SpecPath
-from openapi_core.types import NoValue
 from openapi_core.unmarshalling.schemas.enums import UnmarshalContext
 from openapi_core.unmarshalling.schemas.exceptions import (
     InvalidSchemaFormatValue, InvalidSchemaValue, UnmarshalError,
@@ -158,34 +157,6 @@ def test_string_float_invalid(self, unmarshaller_factory):
         with pytest.raises(InvalidSchemaValue):
             unmarshaller_factory(schema)(value)
 
-    def test_string_default(self, unmarshaller_factory):
-        default_value = 'default'
-        spec = {
-            'type': 'string',
-            'default': default_value,
-        }
-        schema = SpecPath.from_spec(spec)
-        value = NoValue
-
-        result = unmarshaller_factory(schema)(value)
-
-        assert result == default_value
-
-    @pytest.mark.parametrize('default_value', ['default', None])
-    def test_string_default_nullable(
-            self, default_value, unmarshaller_factory):
-        spec = {
-            'type': 'string',
-            'default': default_value,
-            'nullable': True,
-        }
-        schema = SpecPath.from_spec(spec)
-        value = NoValue
-
-        result = unmarshaller_factory(schema)(value)
-
-        assert result == default_value
-
     def test_string_format_date(self, unmarshaller_factory):
         spec = {
             'type': 'string',
@@ -361,19 +332,6 @@ def test_integer_enum_string_invalid(self, unmarshaller_factory):
         with pytest.raises(UnmarshalError):
             unmarshaller_factory(schema)(value)
 
-    def test_integer_default(self, unmarshaller_factory):
-        default_value = 123
-        spec = {
-            'type': 'integer',
-            'default': default_value,
-        }
-        schema = SpecPath.from_spec(spec)
-        value = NoValue
-
-        result = unmarshaller_factory(schema)(value)
-
-        assert result == default_value
-
     def test_integer_default_nullable(self, unmarshaller_factory):
         default_value = 123
         spec = {