To configure Merb to use compass do the following:

Add dependencies to config/dependencies.rb

dependency "haml", ">=2.2.0" dependency "merb-haml", merb_gems_version dependency "chriseppstein-compass", :require_as => ‘compass‘

To use a different sass stylesheets locations as is recommended by compass add this configuration to your configuration block:

Merb::BootLoader.before_app_loads do

  Merb::Plugins.config[:compass] = {
    :stylesheets => "app/stylesheets",
    :compiled_stylesheets => "public/stylesheets/compiled"
  }

end