This paper explores the meaning and applicability of multilevel interventions and the role of ethnography in identifying intervention opportunities and accounting for research design limitations. It utilizes as a case example the data and experiences from a 6-year, NIMH-funded, intervention to prevent HIV/STI among married men in urban poor communities in Mumbai, India. The experiences generated by this project illustrate the need for multilevel interventions to include: (1) ethnographically driven formative research to delineate appropriate levels, stakeholders and collaborators; (2) identification of ways to link interventions to the local culture and community context; (3) the development of a model of intervention that is sufficiently flexible to be consistently applied to different intervention levels using comparable culturally congruent concepts and approaches; (4) mechanisms to involve community residents, community based organizations and community-based institutions; and (5) approaches to data collection that can evaluate the impact of the project on multiple intersecting levels.