2 files changed, 11 insertions, 0 deletions
diff --git a/django/core/serializers/__init__.py b/django/core/serializers/__init__.py
index 7afc94c1d0..09bcb651d5 100644
--- a/django/core/serializers/__init__.py
+++ b/django/core/serializers/__init__.py
@@ -18,6 +18,7 @@ To add your own serializers, use the SERIALIZATION_MODULES setting::
 
 from django.conf import settings
 from django.utils import importlib
+from django.core.serializers.base import SerializerDoesNotExist
 
 # Built-in serializers
 BUILTIN_SERIALIZERS = {
@@ -60,11 +61,15 @@ def unregister_serializer(format):
     "Unregister a given serializer. This is not a thread-safe operation."
     if not _serializers:
         _load_serializers()
+    if format not in _serializers:
+        raise SerializerDoesNotExist(format)
     del _serializers[format]
 
 def get_serializer(format):
     if not _serializers:
         _load_serializers()
+    if format not in _serializers:
+        raise SerializerDoesNotExist(format)
     return _serializers[format].Serializer
 
 def get_serializer_formats():
@@ -80,6 +85,8 @@ def get_public_serializer_formats():
 def get_deserializer(format):
     if not _serializers:
         _load_serializers()
+    if format not in _serializers:
+        raise SerializerDoesNotExist(format)
     return _serializers[format].Deserializer
 
 def serialize(format, queryset, **options):
diff --git a/django/core/serializers/base.py b/django/core/serializers/base.py
index cdcc7fa36a..6afaf216a8 100644
--- a/django/core/serializers/base.py
+++ b/django/core/serializers/base.py
@@ -8,6 +8,10 @@ from django.db import models
 from django.utils.encoding import smart_str, smart_unicode
 from django.utils import datetime_safe
 
+class SerializerDoesNotExist(KeyError):
+    """The requested serializer was not found."""
+    pass
+
 class SerializationError(Exception):
     """Something bad happened during serialization."""
     pass