Behavioral surveillance surveys (BSS) are cross-sectional surveys that provide information on the HIV/AIDS-related knowledge, attitudes, and behaviors of vulnerable sub-populations. There were six target population groups for the Mahārāshtra BSS: brothel based female sex workers, non-brothel based female sex workers, men who have sex with men, local transport workers aged 20-49 years, and single male slum youth aged 15-19 years.