diff --git a/go/contacts/tasks.py b/go/contacts/tasks.py
index 9b1b90c47..56ba1da34 100644
--- a/go/contacts/tasks.py
+++ b/go/contacts/tasks.py
@@ -149,6 +149,16 @@ def export_contacts(account_key, contact_keys, include_extra=True):
 
     api = VumiUserApi.from_config_sync(account_key, settings.VUMI_API_CONFIG)
     contact_store = api.contact_store
+    all_key_count = len(contact_keys)
+
+    message_content_template = 'Please find the CSV data for %s contact(s)'
+
+    if all_key_count > settings.CONTACT_EXPORT_TASK_LIMIT:
+        contact_keys = contact_keys[:settings.CONTACT_EXPORT_TASK_LIMIT]
+        message_content_template = '\n'.join([
+            'NOTE: There are too many contacts to export.',
+            'Please find the CSV data for %%s (out of %s) contacts.' % (
+                all_key_count,)])
 
     contacts = contacts_by_key(contact_store, *contact_keys)
     data = contacts_to_csv(contacts, include_extra)
@@ -159,8 +169,7 @@ def export_contacts(account_key, contact_keys, include_extra=True):
     user_profile = UserProfile.objects.get(user_account=account_key)
 
     email = EmailMessage(
-        'Contacts export',
-        'Please find the CSV data for %s contact(s)' % len(contacts),
+        'Contacts export', message_content_template % len(contacts),
         settings.DEFAULT_FROM_EMAIL, [user_profile.user.email])
 
     email.attach('contacts-export.zip', file, 'application/zip')
diff --git a/go/contacts/tests.py b/go/contacts/tests.py
index 54652098c..f0fd6456d 100644
--- a/go/contacts/tests.py
+++ b/go/contacts/tests.py
@@ -221,6 +221,64 @@ def test_contact_exporting(self):
         self.assertTrue(contents)
         self.assertEqual(mime_type, 'application/zip')
 
+    def test_contact_exporting_too_many(self):
+        """
+        If we have too many contacts to export, we only export a subset.
+        """
+        self.vumi_helper.patch_settings(CONTACT_EXPORT_TASK_LIMIT=2)
+
+        c1 = self.mkcontact()
+        c1.extra['foo'] = u'bar'
+        c1.save()
+
+        c2 = self.mkcontact()
+        c2.extra['foo'] = u'baz'
+        c2.save()
+
+        c3 = self.mkcontact()
+        c3.extra['foo'] = u'quux'
+        c3.save()
+
+        response = self.client.post(reverse('contacts:people'), {
+            '_export': True,
+            'contact': [c1.key, c2.key, c3.key],
+        })
+
+        self.assertContains(
+            response,
+            "The export is scheduled and should complete within a few"
+            " minutes.")
+
+        self.assertEqual(len(mail.outbox), 1)
+        [email] = mail.outbox
+        [(file_name, contents, mime_type)] = email.attachments
+
+        self.assertEqual(email.recipients(), [self.user_email])
+        self.assertTrue('Contacts export' in email.subject)
+        self.assertTrue(
+            'NOTE: There are too many contacts to export.' in email.body)
+        self.assertTrue('2 (out of 3) contacts' in email.body)
+        self.assertEqual(file_name, 'contacts-export.zip')
+
+        zipfile = ZipFile(StringIO(contents), 'r')
+        csv_contents = zipfile.open('contacts-export.csv', 'r').read()
+
+        [header, c1_data, c2_data, _] = csv_contents.split('\r\n')
+
+        self.assertEqual(
+            header,
+            ','.join([
+                'key', 'name', 'surname', 'email_address', 'msisdn', 'dob',
+                'twitter_handle', 'facebook_id', 'bbm_pin', 'gtalk_id',
+                'mxit_id', 'wechat_id', 'created_at', 'foo']))
+
+        self.assertTrue(c1_data.startswith(c1.key))
+        self.assertTrue(c1_data.endswith(',bar'))
+        self.assertTrue(c2_data.startswith(c2.key))
+        self.assertTrue(c2_data.endswith(',baz'))
+        self.assertTrue(contents)
+        self.assertEqual(mime_type, 'application/zip')
+
     def test_exporting_all_contacts(self):
         c1 = self.mkcontact()
         c1.extra['foo'] = u'bar'
diff --git a/go/settings.py b/go/settings.py
index e2cf00f88..db2d31e85 100644
--- a/go/settings.py
+++ b/go/settings.py
@@ -309,6 +309,10 @@ def static_paths(paths):
     # },
 }
 
+
+# Exporting hundreds of thousands of contacts makes celery use all the memory.
+CONTACT_EXPORT_TASK_LIMIT = 100000
+
 try:
     from production_settings import *
 except ImportError as err: