diff --git a/letsencrypt/cli.py b/letsencrypt/cli.py
index 798a816af..4b0e271f7 100644
--- a/letsencrypt/cli.py
+++ b/letsencrypt/cli.py
@@ -147,7 +147,7 @@ def install(args, config, plugins):
     acme, doms = _common_run(
         args, config, acc, authenticator=None, installer=installer)
     assert args.cert_path is not None
-    acme.deploy_certificate(doms, acc.key, args.cert_path, args.chain_path)
+    acme.deploy_certificate(doms, acc.key.file, args.cert_path, args.chain_path)
     acme.enhance_config(doms, args.redirect)