diff --git a/debug.gemspec b/debug.gemspec
index 2a5891f32..b0d0f7139 100644
--- a/debug.gemspec
+++ b/debug.gemspec
@@ -29,4 +29,5 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "irb", "~> 1.10" # for irb:debug integration
   spec.add_dependency "reline", ">= 0.3.8"
+  spec.add_dependency "base64"
 end