Background: HBV (Hepatitis B Virus) and HCV (Hepatitis C Virus) infections are more prevalent in vulnerable populations than the general population. The objective of this study was to investigate the prevalence of HBV and HCV infection in HIV-positive patients (GI), chronic renal failure (CRF) patients (GII) and coagulation disorder individuals (GIII). Methods: A cross-sectional study was conducted from June 2014 to March 2015. Serum samples were tested for markers of hepatitis B and C by enzyme-linked immunosorbent assay (ELISA). Sociodemographic, epidemiological, clinical and laboratory data and accompanying statistical analyses were performed using Epi Info™ 7. Results: A total of 348 individuals were recruited, i.e., 154 HIV-positive, 143 CRF and 51 coagulopathy patients. Among them, more than 66% were men, and the predominant age group was 26-35 years in GI and 56-65 years in GIII. Most patients had more than 8 years of education (66.2% in GI, 60.6% in GIII and 46.1% in GII), with a family income between 100-400 dollars in more than 48% of patients. The prevalence of the HBsAg marker was 3.9%, 7% and 3.9%, total anti-HBc was 28.6%, 55.9% and 31.4%, and anti-HCV was 1.3%, 12.6% and 47% for GI, GII and GIII, respectively. However, the prevalence of anti-HBs was greater than 70% in all groups. Conclusions: This study shows a high prevalence of HBV and HCV among specific groups compared to the general population. Factors such as age, income, number of sexual partners, sexually transmitted disease burden, blood transfusion history or blood products and blood transfusions before 1994 were associated with a higher prevalence for these infections.