ABSTRACT BACKGROUND: Hepatitis B and C virus (HBV and HCV) are the two most common infections among human immunodeficiency virus (HIV)-infected patients. OBJECTIVE: To identify the frequency of HIV subtypes and HCV genotypes in HIV-coinfected patients. METHODS: A cross-sectional and retrospective study was carried out into two reference centers in Southern Brazil between January 1, 2002 and June 30, 2016. The Abbott Real Time HCV Genotype II system was used for routine diagnostics to determine the HCV genotype based on dual-target real-time PCR. Proviral HIV-1 RNA was extracted from serum samples and fragments of the pol gene were generated by PCR. The HIV-1 PT and RT gene sequences were submitted to Maximum Likelihood Phylogenetic analysis by collecting reference sequences from the HIV-1 group M subtype of the Los Alamos database. RESULTS: During the study period, 3340 patients with HIV were diagnosed at both referral centers, of which 4.97% (166/3340) had HBV and/or HCV coinfection. Seroprevalence of HIV-HBV, HIV-HCV and HIV-HBV-HCV was 37.4%, 58.4%, and 4.2%, respectively. HIV-HCV-coinfected patients had a lower median nadir CD4+ T-cell count when compared to HIV-HBV-coinfected patients (P=0.01). Among those coinfected with HCV, HCV-1 (HCV-1) and HCV-3 (HCV-3) genotypes were the most prevalent, being detected in 73.8% and 21.4%, respectively. Among the HCV-1 coinfected patients, 79.3% and 20.1% had subtypes 1a and 1b, respectively. HIV subtype B was the most prevalent in HIV-coinfected patients. There was no significant difference regarding nadir CD4+ T-cell count and HIV viral load when compared to coinfected with HCV-1 with HCV-3, as well as those co-infected with HCV-1a with HCV-1b. CONCLUSION: In the present study, a higher frequency of subtype B of HIV and HCV-1 were found in HIV-coinfected patients. Further larger-scale and long-term studies are needed to better understand the effect of HCV genotypes in HIV-infected patients.