diff --git a/requirements.txt b/requirements.txt
index 641a055f..69372c63 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -15,9 +15,9 @@ PyYAML==3.11
 redis==2.10.5
 requests==2.10.0
 Shapely==1.4.3
-simplejson==3.6.4
 six==1.10.0
 StreetNames==0.1.5
+ujson==1.35
 Werkzeug==0.9.6
 wsgiref==0.1.2
 zope.dottedname==4.1.0
diff --git a/setup.py b/setup.py
index 8db2daf9..72e03ca1 100644
--- a/setup.py
+++ b/setup.py
@@ -47,6 +47,7 @@
           'redis',
           'requests',
           'Shapely',
+          'ujson',
           'zope.dottedname',
       ],
       test_suite='tests',
diff --git a/tilequeue/format/geojson.py b/tilequeue/format/geojson.py
index 421b1f80..7f052d9f 100644
--- a/tilequeue/format/geojson.py
+++ b/tilequeue/format/geojson.py
@@ -1,6 +1,6 @@
 from math import ceil
 from math import log
-import json
+import ujson as json
 import shapely.geometry
 import shapely.ops
 import shapely.wkb
diff --git a/tilequeue/format/topojson.py b/tilequeue/format/topojson.py
index 2dedbcda..1af0c0a1 100644
--- a/tilequeue/format/topojson.py
+++ b/tilequeue/format/topojson.py
@@ -1,4 +1,4 @@
-import json
+import ujson as json
 
 
 def update_arc_indexes(geometry, merged_arcs, old_arcs):