Objective: The aim of this study is to describe the single nucleotide polymorphisms (SNP) in human genes for IL28B and ITPA of HIV/HCV coinfected patients followed at a referral Hospital of Universidade Federal do Paraná (UFPR). Methods: A cross-sectional study was carried out. HIV/HCV coinfected and HCV monoinfected patients were enrolled. Clinical and epidemiological data from medical records were reviewed, and peripheral blood was collected to analyze the IL28B and ITPA SNPs. Results: A total of 37 HCV-and 41 HCV/HIV-positive subjects were included in the study, 13 (35.1%) monoinfected subjects were previously treated, 12 (92.3%) with PEG-INFα/RBV and of these, 8 (61.5%) had sustained virological response (SVR). Regarding HCV/HIV coinfected patients, 23 (56.1%) received treatment with PEG-INFα/RBV and 12 (52.1%) had SVR. IL28B CC genotype was found in all HCV monoinfected patients and in 56.5% of coinfected subjects. Regarding ribavirin-induced anemia, all patients showed the ITPA SNP favorable for this event, and anemia was present in 38.5% of monoinfected and in 65.2% of coinfected patients. Conclusion: With the availability of direct-acting antivirals (DAAs) for the treatment of chronic infection by the hepatitis C virus, free-INF regimens have been implemented worldwide. However, in the setting of HIV/HCV coinfection ribavirin will continue to compose some therapeutic schemes. Thus, tests related to genetic markers that influence the response to HCV treatment should be recommended in pretreatment, since results would benefit both the patient and the public healthcare system, guiding rational drug use in situations where responses to treatment are particularly low and adverse effects are high.