The Sonagachi Project, in Kolkata, India, was an intervention project that sought to empower and protect sex workers and reduce their vulnerability to contracting HIV by creating social spaces for participation, community led projects and outreach, and organizing rallies and protests for rights and healthy behaviors. Interviews and focus groups with study participants revealed that a lack of control over material resources, exclusion from social participation, and a lack of control over their lives were key inhibitors to empowerment. The study surfaced strategies to reduce vulnerability of sex workers, including promoting the right to self-determination. The project has helped sex workers substantially increase control over their sexual health, as well as improve their living conditions and working environment; it also placed sex work issues on state and national policy agendas.