Objective Whether concomitant HIV antiretroviral therapy (ART) affects the safety and efficacy of interferon‐free HCV therapies or whether HCV treatment may negatively affect HIV control is unclear. We assessed the 3 direct‐acting antiviral (3D) regimen of ombitasvir, ABT‐450 (identified by AbbVie and Enanta; co‐dosed with ritonavir) and dasabuvir with ribavirin (RBV) in HCV/HIV‐1 co‐infected patients with and without cirrhosis, including HCV treatment‐experienced, receiving atazanavir (ATV)‐ or raltegravir (RAL)‐based ART therapy. Methods HCV genotype 1‐positive treatment‐naïve or pegIFN/RBV‐experienced patients, with or without Child‐Pugh A cirrhosis, CD4+ count ≥200 cells/mm3 or CD4 + % ≥14%, and plasma HIV‐1 RNA suppressed on stable ART received open‐label 3D + RBV for 12 or 24 weeks. Rates of HCV‐sustained virologic response at post‐treatment weeks 4 and 12 (SVR4 and SVR12, respectively) and bilirubin‐related adverse events (AEs) are reported from post‐hoc analyses for subgroups defined by treatment duration and ART regimen. Results The SVR12 rate for patients receiving 12 weeks of 3D + RBV was 93.5% with comparable rates in patients receiving either ATV (93.8%) or RAL therapy (93.3%) (Table 1). The SVR4 rate for the 24‐week arm was 96.9% with a single virologic breakthrough at treatment week 16 in a patient receiving RAL therapy. Patients receiving concomitant ATV had more AEs related to indirect hyperbilirubinemia including ocular icterus, jaundice and grade 3 or 4 elevations in total bilirubin (predominantly indirect). No patient discontinued the study due to AEs, and no serious AEs were reported during or after treatment. No patient had a confirmed plasma HIV‐1 RNA value ≥200 copies/mL during the treatment period. Conclusions In this first study to evaluate an IFN‐free regimen in HCV genotype 1‐positive treatment‐naïve and experienced patients with HIV‐1 co‐infection, including those with cirrhosis, high rates of SVR were comparable to those with HCV monoinfection. Indirect hyperbilirubinemia was consistent with the known ABT‐450 inhibition of the OATP1B1 bilirubin transporter, RBV‐related haemolytic anaemia and inhibitory effect of ATV on bilirubin conjugation. The laboratory abnormalities and AEs observed did not negatively affect treatment response or lead to treatment discontinuation.