A presentation by the Bill and Melinda Gates Foundation at the Mexico IAS Conference – NACO Satellite Session August 3, 2008. It provides a thorough account of how the Foundation’s HIV prevention project in India, Avahan, mobilises communities to deliver HIV prevention and care services to female sex workers and ‘MSM’ and transgender sex workers. This community mobilization has involved addressing a range of challenges so there is much to learn from the AVAHAN initiative see their website.