diff --git a/lib/snmp/ber.rb b/lib/snmp/ber.rb
index b80e4f7..e8ce357 100644
--- a/lib/snmp/ber.rb
+++ b/lib/snmp/ber.rb
@@ -1,3 +1,4 @@
+# encoding: ascii-8bit
 #
 # Copyright (c) 2004 David R. Halliday
 # All rights reserved.
diff --git a/test/test_ber.rb b/test/test_ber.rb
index 360c3db..b55d394 100644
--- a/test/test_ber.rb
+++ b/test/test_ber.rb
@@ -1,3 +1,5 @@
+# encoding: ascii-8bit
+
 require 'test/unit'
 require 'snmp/varbind'
 require 'snmp/ber'