diff --git a/tubular/scripts/retrieve_latest_base_ami.py b/tubular/scripts/retrieve_latest_base_ami.py
index 69a33823..10436974 100755
--- a/tubular/scripts/retrieve_latest_base_ami.py
+++ b/tubular/scripts/retrieve_latest_base_ami.py
@@ -15,6 +15,7 @@
 import click
 import yaml
 import requests
+import backoff
 
 # Add top-level module path to sys.path before importing tubular code.
 sys.path.append(path.dirname(path.dirname(path.abspath(__file__))))