Background. Hepatitis B virus (HBV), a highly contagious virus, is a circular partial double-stranded DNA virus. Hepatitis C virus (HCV) is an enveloped, single-stranded RNA virus with a major blood-borne infection worldwide. Infection of HBV and HCV among blood donors is an important public health problem. Objective. To assess the seroprevalence of hepatitis B and C viruses and associated factors among blood donors at Bahir Dar Blood Bank, Northwest Ethiopia. Method. Institutional-based cross-sectional study was conducted at Bahir Dar Blood Bank from May 18, 2020 to July 27, 2020. A systematic random sampling technique was used to select 426 participants. Variables having a p value of <0.05 with 95% CI and AOR were considered statistically significant. Results. From 426 proposed participants, 418 (98.1%) of them completed the face-to-face interview. The seroprevalence of HBV and HCV among study participants was 4.07% and 0.48%, respectively. Having multiple sexual partners (AOR = 10.356: 95% CI: (2.277–47.099)), having a family history of hepatitis (AOR = 8.106: 95% CI: (1.278–51.403)), and having sharp materials sharing experience (AOR = 11.313, 95% CI: (1.144–111.864)) have a significant association with HBV infection. No risk factors were found for HCV infectious markers. Conclusion and Recommendations. This study showed that the seroprevalence of HBV and HCV infections confirmed with positive tests among voluntary blood donors in Bahir Dar Blood Bank was 4.07% and 0.48%, respectively. HBV seroprevalence among blood donors in this study has remained stable when compared to a study done in 2013 in the same population. Strict donor selection, safe sex practice, using proper safety precautions when offering care to a family member, and immunization of people at risk could constitute an important package of a prevention program.