diff --git a/travis_config.rb b/travis_config.rb
index 0ba2c38f1a..040b1a255b 100644
--- a/travis_config.rb
+++ b/travis_config.rb
@@ -1,10 +1,6 @@
 MRuby::Build.new do |conf|
   toolchain :gcc
 
-  conf.gem "#{root}/mrbgems/mruby-sprintf"
-  conf.gem "#{root}/mrbgems/mruby-print"
-
-  Dir.glob("#{root}/mrbgems/mruby-*") do |x|
-    conf.gem x unless x =~ /\/mruby-(print|sprintf)$/
-  end
+  # include all core GEMs
+  conf.gembox 'full-core'
 end