The preliminary results indicated that the risk profiles for HIV/sexually transmitted disease infection differed among the FSWs in these two cities on the Mexico-United States border. Specifically, while the HIV prevalence among the FSWs in Tijuana and Ciudad Juarez were similar (4.8 percent and 4.9 percent, respectively), the FSWs in Ciudad Juarez were more likely to test positive for syphilis (31.3 percent) than were the FSWs in Tijuana (11.8 percent). The two groups did not differ significantly on the prevalence of gonorrhea or chlamydia. FSWs in both cities reported high levels of unprotected sex and drug use but the FSWs in Ciudad Juarez were more likely than the FSWs in Tijuana to have ever injected drugs (75 percent versus 25 percent, respectively). Cocaine and heroin use were also more common among the FSWs in Ciudad Juarez. The findings revealed that being younger, working in Ciudad Juarez, and using heroin or cocaine were associated with syphilis infection while methamphetamine use among FSWs in Tijuana was associated with syphilis infection. The findings of differences between the risk profiles for the FSWs in each city suggest the need to tailor interventions of the specific needs of the populations of each city. Participants were 155 FSWs in Tijuana and 140 FSWs in Ciudad Juarez who were recruited through municipal and community health clinics to complete an interviewer-administered survey, a blood draw, and a cervical swab. The survey focused on sociodemographic information, sexual risk behaviors with nonclient partners as well as regular and nonregular clients, and drug use patterns. The blood and cervical samples were analyzed for the presence of HIV and other sexually transmitted diseases. Data analysis involved the use of t-tests, Pearson chi-square tests, and multiple regression models. Future research should broaden the population under study. Tables, references