diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index 4594da95ac..11c7a5ed9a 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -835,7 +835,10 @@ class ForeignKey(RelatedField, Field):
         if value is None:
             return
 
-        qs = self.rel.to._default_manager.filter(**{self.rel.field_name:value})
+        using = router.db_for_read(model_instance.__class__, instance=model_instance)
+        qs = self.rel.to._default_manager.using(using).filter(
+                **{self.rel.field_name: value}
+             )
         qs = qs.complex_filter(self.rel.limit_choices_to)
         if not qs.exists():
             raise exceptions.ValidationError(self.error_messages['invalid'] % {
diff --git a/tests/regressiontests/multiple_database/tests.py b/tests/regressiontests/multiple_database/tests.py
index 22ee74c697..04ab2bb925 100644
--- a/tests/regressiontests/multiple_database/tests.py
+++ b/tests/regressiontests/multiple_database/tests.py
@@ -581,6 +581,12 @@ class QueryTestCase(TestCase):
         self.assertEquals(Person.objects.using('other').count(), 0)
         self.assertEquals(Pet.objects.using('other').count(), 0)
 
+    def test_foreign_key_validation(self):
+        "ForeignKey.validate() uses the correct database"
+        mickey = Person.objects.using('other').create(name="Mickey")
+        pluto = Pet.objects.using('other').create(name="Pluto", owner=mickey)
+        self.assertEquals(None, pluto.full_clean())
+
     def test_o2o_separation(self):
         "OneToOne fields are constrained to a single database"
         # Create a user and profile on the default database