diff --git a/etc/nova/nova.conf.sample b/etc/nova/nova.conf.sample
index 879838eb7d3b..e03b8363ed79 100644
--- a/etc/nova/nova.conf.sample
+++ b/etc/nova/nova.conf.sample
@@ -1440,7 +1440,7 @@
 
 ######## defined in nova.virt.libvirt.imagecache ########
 
-# remove_unused_base_images=false
+# remove_unused_base_images=true
 #### (BoolOpt) Should unused base images be removed?
 
 # remove_unused_resized_minimum_age_seconds=3600
diff --git a/nova/virt/libvirt/imagecache.py b/nova/virt/libvirt/imagecache.py
index 01c0046a01d3..9825cc689230 100644
--- a/nova/virt/libvirt/imagecache.py
+++ b/nova/virt/libvirt/imagecache.py
@@ -42,7 +42,7 @@ LOG = logging.getLogger(__name__)
 
 imagecache_opts = [
     cfg.BoolOpt('remove_unused_base_images',
-                default=False,
+                default=True,
                 help='Should unused base images be removed?'),
     cfg.IntOpt('remove_unused_resized_minimum_age_seconds',
                default=3600,