diff --git a/tests/letstest/multitester.py b/tests/letstest/multitester.py
index 430acb634..27b9e693a 100644
--- a/tests/letstest/multitester.py
+++ b/tests/letstest/multitester.py
@@ -106,6 +106,11 @@ EC2 = None
 SECURITY_GROUP_NAME = 'certbot-security-group'
 SUBNET_NAME = 'certbot-subnet'
 
+class Status(object):
+    """Possible statuses of client tests."""
+    PASS = 'pass'
+    FAIL = 'fail'
+
 # Boto3/AWS automation functions
 #-------------------------------------------------------------------------------
 def should_use_subnet(subnet):
@@ -357,10 +362,10 @@ def test_client_process(inqueue, outqueue):
 
         try:
             install_and_launch_certbot(instances[ii], boulder_url, target)
-            outqueue.put((ii, target, 'pass'))
+            outqueue.put((ii, target, Status.PASS))
             print("%s - %s SUCCESS"%(target['ami'], target['name']))
         except:
-            outqueue.put((ii, target, 'fail'))
+            outqueue.put((ii, target, Status.FAIL))
             print("%s - %s FAIL"%(target['ami'], target['name']))
             traceback.print_exc(file=sys.stdout)
             pass
@@ -559,17 +564,24 @@ try:
     results_file = open(LOGDIR+'/results', 'w')
     outputs = [outq for outq in iter(outqueue.get, SENTINEL)]
     outputs.sort(key=lambda x: x[0])
+    failed = False
     for outq in outputs:
         ii, target, status = outq
+        if status == Status.FAIL:
+            failed = True
         print('%d %s %s'%(ii, target['name'], status))
         results_file.write('%d %s %s\n'%(ii, target['name'], status))
     if len(outputs) != num_processes:
+        failed = True
         failure_message = 'FAILURE: Some target machines failed to run and were not tested. ' +\
             'Tests should be rerun.'
         print(failure_message)
         results_file.write(failure_message + '\n')
     results_file.close()
 
+    if failed:
+        sys.exit(1)
+
 finally:
     cleanup(cl_args, instances, targetlist)