Genital ulcer disease (GUD) is common in HIV-1-infected women, and a small number of studies have suggested increased GUD risk after antiretroviral therapy (ART) initiation. To better define this risk, we monitored 134 women at ART initiation and monthly thereafter. Women were evaluated monthly for genital ulcers. Syphilis serology was tested quarterly, and chancroid culture was performed on ulcers that were felt to be clinically consistent with a diagnosis of chancroid. A logistic model with generalized estimating equations was used to analyze predictors of GUD from baseline until 6 months after ART initiation. During the study period, GUD occurred in 54 women (40.3%) at 85 visits (10.0%). GUD prevalence was 9.7% at baseline, increased to 16.7% at month 1 [adjusted odds ratio (aOR) 1.9 (1.0-3.6), P = 0.04], then decreased to 6.4% by month 6. History of GUD [aOR 3.8 (1.9-7.7), P < 0.001) and CD4 count <100 [aOR 1.8 (1.0-3.4), P = 0.06] were associated with increased risk of GUD after ART initiation. Women experience increased risk of GUD in the first month after ART initiation, particularly if they have low CD4 counts or a history of GUD.