Steps to ensure Haml works: 1. In config/application.rb, be sure to add Haml as a template_engine. config.generators do |g| g.template_engine :haml end 2. Run haml –rails . to initialize Haml under Rails. 3. Rails 3 generators for Haml are at: http://github.com/pjb3/rails3-generators. Passenger 2.2.9 is fully compatible with Rails 3. Though if you wish to take advantage of REE's optimizations you