U.S. guidelines recommend that patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) be prioritized for HCV treatment with direct-acting antiviral agents (DAAs), but the high cost of DAAs may contribute to disparities in treatment uptake and outcomes. We evaluated DAA initiation and effectiveness in HIV/HCV-coinfected patients in a U.S.-based healthcare system during October 2014-December 2017. Of 462 HIV/HCV-coinfected patients, 276 initiated DAAs (70% cumulative proportion treated over three years). Lower likelihood of DAA initiation was observed among patients with Medicare (government-sponsored insurance) versus commercial insurance (adjusted rate ratio [aRR] = 0.62, 95% CI = 0.46-0.84), patients with drug abuse diagnoses (aRR = 0.72, 95% CI = 0.54-0.97), patients with CD4 cell count <200 cells/µl versus ≥500 (aRR = 0.45, 95% CI = 0.23-0.91), and patients without prior HCV treatment (aRR = 0.68, 95% CI = 0.48-0.97). There were no significant differences in DAA initiation by age, gender, race/ethnicity, socioeconomic status, HIV transmission risk, alcohol use, smoking, fibrosis level, HIV RNA levels, antiretroviral therapy use, hepatitis B infection, or number of outpatient visits. Ninety-five percent of patients achieved sustained virologic response (SVR). We found little evidence of sociodemographic disparities in DAA initiation among HIV/HCV-coinfected patients, and SVR rates were high. Efforts are needed to increase DAA uptake among coinfected Medicare enrollees, patients with drug abuse diagnoses, patients with low CD4 cell count, and patients receiving first-time HCV treatment.