The objective of this study was to determine the seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections and the possible risk factors among blood donors in Nyala, South Dar Fur State of western Sudan, which has never been studied before. A total of 400 male blood donors were tested for the detection of HBsAg and anti-HCV antibodies, (6.25%) were found reactive for HBsAg and (0.65%) were reactive for anti-HCV antibodies. The highest seroprevalence (30.8%) was found in those between 19-24 and 37-42 years for HBsAg, whereas it was (50%) in those between 31-36 years for anti-HCV antibodies. Unprotected sexual activities (20%) was the most apparent predisposing risk factor for both HBV and HCV seroreactors, followed by razor sharing (13.3%), parenteral drug injections (10%), history of migration to Egypt and alcoholism (6.6%) for each, tattooing and surgical procedures (3.3%) for each and (36.6%) were not aware for their condition. Serum alanine aminotansferase (ALT) was elevated in (30.7%) of HBV seroreactors and in (50%) of HCV seroreactors. Serum albumin was reduced in (23.1%) HBV and in (50%) HCV seroreactors. The study concluded that the seroprevalence of HBV and HCV was in an intermediate and low rates respectively and unprotected sexual activities was the major risk factor for infection in the population studied.