diff --git a/manifests/os/debian.pp b/manifests/os/debian.pp
index 5d8f68af91d2afb3cb8b7760d9f01d4a0e98312a..a23351908c30b5a9a27d16c9b234073beb2ee537 100644
--- a/manifests/os/debian.pp
+++ b/manifests/os/debian.pp
@@ -66,10 +66,11 @@ class base::os::debian (
 
   # Install APT sources configuration.  This is generally handled via
   # templates.
+  # NOTE: We hold off on messing with the master sources list until we've
+  # created the other sources files.  We do this to ensure that a source
+  # never gets removed entirely.  Luckily, `aptitude update` doesn't error
+  # out if a source is listed multiple times.
   file {
-    '/etc/apt/sources.list':
-      content => template('base/os/sources/sources.list.erb'),
-      notify  => Exec['aptitude update'];
     '/etc/apt/sources.list.d':
       ensure  => 'directory',
       recurse => true,
@@ -81,6 +82,13 @@ class base::os::debian (
     '/etc/apt/sources.list.d/stanford.list':
       content => template('base/os/sources/stanford.list.erb'),
       notify  => Exec['aptitude update'];
+    '/etc/apt/sources.list':
+      content => template('base/os/sources/sources.list.erb'),
+      require => [
+                  File['/etc/apt/sources.list.d/backports.list'],
+                  File['/etc/apt/sources.list.d/stanford.list'],
+                 ],
+      notify  => Exec['aptitude update'];
   }
 
   # Install APT preferences.  We should never use /etc/apt/preferences