We conducted this study to determine the prevalence and risk factors for HIV-1 infection among women (N = 312) who were working in the bars and hotels in Moshi, a town in northern Tanzania. Study subjects were interviewed to obtain information about HIV-1 risk factors and examined to collect samples for the diagnosis of sexually transmitted diseases (STDs). The prevalence of HIV-1 was 26.3% (95% confidence interval [CI], 21.4%-31.2%). In multivariate analyses, the risk of HIV-1 increased with increasing age (p value, test for linear trend <.001) and the number of sexual partners during the last 5 years (p value, test for linear trend <.03). Other significant predictors were having a male partner with other sexual partners (Adjusted odds ratio [AOR], 1.92; 95% CI, 1.03-3.60), and consuming alcohol >2 days per week (AOR, 2.56; 95% CI, 1.12-5.88). The risk of HIV-1 was also significantly increased in women with bacterial vaginosis (AOR, 2.37; 95% CI, 1.09-5.13) and in study subjects with herpes simplex virus (HSV)-2 antibodies (AOR, 2.48; 95% CI, 1.24-4.98). These results indicate that women working in these settings were at increased risk of HIV-1. Programs aiming at promoting safer sexual practices and control of other STDs are urgently needed in this population. Such programs should address the underlying conditions that facilitate risk behaviors and create obstacles for these women who wish to protect themselves against HIV-1.