Sexually transmitted infections (STIs) and HIV infection are increasing at an alarming rate in Mexico (United Nations Program on AIDS [UNAIDS], 2006). Female sex workers (FSWs) are one of the groups affected by the increase in HIV prevalence in Mexico. Early surveillance of FSWs found seroprevalence rates of 4.8% in Tijuana and 4.9% in Ciudad Juarez, Mexico (Patterson et al., 2006b), while the most recent study of FSWs from these two cities found a seroprevalence rate of 6% (Strathdee et al, in press). Prevention efforts that are culturally sensitive and appropriately tailored are needed to stem the rise of HIV in this high-risk population. The current study examined the applicability of the Social Ecological model for HIV prevention in a sample of female sex workers (FSWs) (N=472) participating in a safe sex counseling intervention in Tijuana, Mexico. Within the framework of the Social Ecological Model we explored differential predictors of condom use by comparing women who work in bar settings to those who work on the street hypothesizing that there would be differences across venue (bar vs street) with higher condom use in bar workers. Baseline models were established using path analysis in bar (N=233); (CFI= .890, RMSEA =.062) and street workers (N=203); (CFI =.928, RMSEA = .040). For bar workers individual level factors, (self-efficacy, condom use beliefs, alcohol use before sex) and institutional level factors (condom access) were directly and indirectly related to condom use, while in street workers interpersonal level factors (social support, previous abuse, client power) and drug use were the most important factors associated with condom use. Multiple group partial structural invariance was then performed comparing street workers (N=79) to bar workers (N=103) on the 5 paths that their baseline models shared, showing that these paths were invariant across groups ([delta][chi]²(5) =6.30). Multiple group comparisons found similarities between the bar and street workers, including the relationship between self-efficacy and condom use. Baseline model comparisons found differences including the type of substance used before sex, and the relationship between monetary incentives for unprotected sex and condom use self- efficacy, supporting the need for the tailoring of interventions for women based on location of their sex work