diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 491aa7eda..fc14184cc 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -383,7 +383,6 @@ class URLField(CharField):
     type_name = 'URLField'
 
     def __init__(self, **kwargs):
-        kwargs['max_length'] = kwargs.get('max_length', 200)
         kwargs['validators'] = [validators.URLValidator()]
         super(URLField, self).__init__(**kwargs)
 
@@ -392,7 +391,6 @@ class SlugField(CharField):
     type_name = 'SlugField'
 
     def __init__(self, *args, **kwargs):
-        kwargs['max_length'] = kwargs.get('max_length', 50)
         super(SlugField, self).__init__(*args, **kwargs)
 
 
diff --git a/rest_framework/tests/fields.py b/rest_framework/tests/fields.py
index cb5b05dc7..d82f6b235 100644
--- a/rest_framework/tests/fields.py
+++ b/rest_framework/tests/fields.py
@@ -688,61 +688,124 @@ class ChoiceFieldTests(TestCase):
         self.assertEqual(f.choices, models.fields.BLANK_CHOICE_DASH + self.SAMPLE_CHOICES)
 
 
+class EmailFieldTests(TestCase):
+    """
+    Tests for EmailField attribute values
+    """
+
+    class EmailFieldModel(RESTFrameworkModel):
+        email_field = models.EmailField(blank=True)
+
+    class EmailFieldWithGivenMaxLengthModel(RESTFrameworkModel):
+        email_field = models.EmailField(max_length=150, blank=True)
+
+    def test_default_model_value(self):
+        class EmailFieldSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = self.EmailFieldModel
+
+        serializer = EmailFieldSerializer(data={})
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(getattr(serializer.fields['email_field'], 'max_length'), 75)
+
+    def test_given_model_value(self):
+        class EmailFieldSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = self.EmailFieldWithGivenMaxLengthModel
+
+        serializer = EmailFieldSerializer(data={})
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(getattr(serializer.fields['email_field'], 'max_length'), 150)
+
+    def test_given_serializer_value(self):
+        class EmailFieldSerializer(serializers.ModelSerializer):
+            email_field = serializers.EmailField(source='email_field', max_length=20, required=False)
+
+            class Meta:
+                model = self.EmailFieldModel
+
+        serializer = EmailFieldSerializer(data={})
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(getattr(serializer.fields['email_field'], 'max_length'), 20)
+
+
 class SlugFieldTests(TestCase):
     """
     Tests for SlugField attribute values
     """
 
-    def test_default_value(self):
-        class SlugFieldModel(RESTFrameworkModel):
-            slug_field = models.SlugField(blank=True)
+    class SlugFieldModel(RESTFrameworkModel):
+        slug_field = models.SlugField(blank=True)
 
+    class SlugFieldWithGivenMaxLengthModel(RESTFrameworkModel):
+        slug_field = models.SlugField(max_length=84, blank=True)
+
+    def test_default_model_value(self):
         class SlugFieldSerializer(serializers.ModelSerializer):
             class Meta:
-                model = SlugFieldModel
+                model = self.SlugFieldModel
 
         serializer = SlugFieldSerializer(data={})
         self.assertEqual(serializer.is_valid(), True)
         self.assertEqual(getattr(serializer.fields['slug_field'], 'max_length'), 50)
 
-    def test_given_value(self):
-        class SlugFieldModel(RESTFrameworkModel):
-            slug_field = models.SlugField(max_length=84, blank=True)
-
+    def test_given_model_value(self):
         class SlugFieldSerializer(serializers.ModelSerializer):
             class Meta:
-                model = SlugFieldModel
+                model = self.SlugFieldWithGivenMaxLengthModel
 
         serializer = SlugFieldSerializer(data={})
         self.assertEqual(serializer.is_valid(), True)
         self.assertEqual(getattr(serializer.fields['slug_field'], 'max_length'), 84)
 
+    def test_given_serializer_value(self):
+        class SlugFieldSerializer(serializers.ModelSerializer):
+            slug_field = serializers.SlugField(source='slug_field', max_length=20, required=False)
+
+            class Meta:
+                model = self.SlugFieldModel
+
+        serializer = SlugFieldSerializer(data={})
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(getattr(serializer.fields['slug_field'], 'max_length'), 20)
+
 
 class URLFieldTests(TestCase):
     """
     Tests for URLField attribute values
     """
 
-    def test_default_value(self):
-        class URLFieldModel(RESTFrameworkModel):
-            url_field = models.URLField(blank=True)
+    class URLFieldModel(RESTFrameworkModel):
+        url_field = models.URLField(blank=True)
 
+    class URLFieldWithGivenMaxLengthModel(RESTFrameworkModel):
+        url_field = models.URLField(max_length=128, blank=True)
+
+    def test_default_model_value(self):
         class URLFieldSerializer(serializers.ModelSerializer):
             class Meta:
-                model = URLFieldModel
+                model = self.URLFieldModel
 
         serializer = URLFieldSerializer(data={})
         self.assertEqual(serializer.is_valid(), True)
         self.assertEqual(getattr(serializer.fields['url_field'], 'max_length'), 200)
 
-    def test_given_value(self):
-        class URLFieldModel(RESTFrameworkModel):
-            url_field = models.URLField(max_length=128, blank=True)
-
+    def test_given_model_value(self):
         class URLFieldSerializer(serializers.ModelSerializer):
             class Meta:
-                model = URLFieldModel
+                model = self.URLFieldWithGivenMaxLengthModel
 
         serializer = URLFieldSerializer(data={})
         self.assertEqual(serializer.is_valid(), True)
-        self.assertEqual(getattr(serializer.fields['url_field'], 'max_length'), 128)
\ No newline at end of file
+        self.assertEqual(getattr(serializer.fields['url_field'], 'max_length'), 128)
+
+    def test_given_serializer_value(self):
+        class URLFieldSerializer(serializers.ModelSerializer):
+            url_field = serializers.URLField(source='url_field', max_length=20, required=False)
+
+            class Meta:
+                model = self.URLFieldWithGivenMaxLengthModel
+
+        serializer = URLFieldSerializer(data={})
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(getattr(serializer.fields['url_field'], 'max_length'), 20)
\ No newline at end of file