Behavioral surveillance surveys (BSS) are cross-sectional surveys that provide information on the HIV/AIDS-related knowledge, attitudes, and behaviors of vulnerable sub-populations. The Laos 2000-2001 BSS covered five of the most populous provinces along Route 13, the main land transportation route of Lao PDR. The target groups within these provinces included male and female cross border seasonal migrant workers, female factory workers, service women, long distance truck drivers, police and military.