Hepatitis C (HCV) and HIV coinfection is common and liver disease is a leading cause of morbidity and mortality among coinfected patients. Despite advances in HCV treatment, few HIV coinfected patients actually initiate treatment. We examined patient and provider characteristics associated with a patient's decision to accept or refuse HCV treatment once offered. We conducted patient chart abstraction and surveys with 127 HIV coinfected patients who were offered HCV treatment by their provider and surveys of their HCV care providers at three HIV clinics. Participants were mostly male (87%), minority (66%), and had a history of injection drug use (60%). Most had been diagnosed with HIV for several years (X=13.7 years) and reported HIV transmission through unprotected sex (47%). Of the 127 patients, 79 accepted treatment. In multivariate analysis, patients who had a CD4 greater than 200 cells/mm(3) and a provider with more confidence about HCV treatment were more likely to accept the recommendation to start treatment; younger age was marginally associated with treatment acceptance. In bivariate analysis, added correlates of treatment acceptance included male gender, no recent drug use, and several provider attitudes regarding treatment and philosophy about determination of patient treatment readiness. Patient and provider characteristics are important when understanding a patient's decision to start or defer HCV treatment. Further research is needed to better understand barriers to treatment uptake as new and more effective HCV treatments will soon be available.