### Install ruby-debug19 with ruby 1.9.3 Download the following gems from http://rubyforge.org/frs/?group_id=8883 * linecache19-0.5.13.gem * ruby-debug-base19-0.11.26.gem gem install ~/Downloads/linecache19-0.5.13.gem You need to point to the directory with the Ruby header files (specifically method.h) and pass it with the gem install command. Should look something like: gem install ~/Downloads/ruby-debug-base19-0.11.26.gem -- --with-ruby-include=~/.rbenv/versions/1.9.3-rc1/include/ruby-1.9.1/ruby-1.9.3-rc1 Add to Gemfile: gem ‘ruby-debug19′, :require => ‘ruby-debug’ Start rails with debugger option: rails server --debugger #### The real hard work was done by: * [http://blog.wyeworks.com/2011/11/1/ruby-1-9-3-and-ruby-debug](http://blog.wyeworks.com/2011/11/1/ruby-1-9-3-and-ruby-debug) * [http://dirk.net/2010/04/17/ruby-debug-with-ruby-19x-and-rails-3-on-rvm/](http://dirk.net/2010/04/17/ruby-debug-with-ruby-19x-and-rails-3-on-rvm/)