AbstractBackgroundMale sex workers are at high-risk for acquisition of sexually transmitted infections (STIs), including human immunodeficiency virus (HIV). We quantified incidence rates of STIs and identified their time-varying predictors among male sex workers in Mexico City.MethodsFrom January 2012 to May 2014, male sex workers recruited from the largest HIV clinic and community sites in Mexico City were tested for chlamydia, gonorrhea, syphilis, hepatitis, and HIV at baseline, 6-months, and 12-months. Incidence rates with 95% bootstrapped confidence limits were calculated. We examined potential time-varying predictors using generalized estimating equations for a population averaged model.ResultsAmong 227 male sex workers, median age was 24 and baseline HIV prevalence was 32%. Incidence rates (per 100 person-years) were as follows: HIV [5.23; 95% confidence interval (CI): 2.15–10.31], chlamydia (5.15; 95%CI: 2.58–9.34), gonorrhea (3.93; 95%CI: 1.88–7.83), syphilis (13.04; 95%CI: 8.24–19.94), hepatitis B (2.11; 95%CI: 0.53–4.89), hepatitis C (0.95; 95%CI: 0.00–3.16), any STI except HIV (30.99; 95%CI: 21.73–40.26), and any STI including HIV (50.08; 95%CI: 37.60–62.55). In the multivariable-adjusted model, incident STI (excluding HIV) were lower among those who reported consistently using condoms during anal and vaginal intercourse (odds ratio = 0.03, 95%CI: 0.00–0.68) compared to those who reported inconsistently using condoms during anal and vaginal intercourse.ConclusionsIncidence of STIs is high among male sex workers in Mexico City. Consistent condom use is an important protective factor for STIs, and should be an important component of interventions to prevent incident infections.