This two-part article discusses serologic testing of prospective donors for viral hepatitis B and C, as part of the comprehensive donor evaluation, and reviews the current policies and practices aimed at preventing donor-to-recipient transmission of hepatitis B and C viruses (HBV, HBC). This first part of the review discusses HBV. Organs procured from HBV-infected donors can transmit the virus to their recipients. Because infections with HBV have been associated with increased morbidity and mortality among renal transplant recipients, it is important to prevent HBV transmission with renal transplantation. Routine serologic evaluation of prospective organ donors for markers of HBV infection includes testing for hepatitis B surface antigen (HBsAg), anti-hepatitis B surface antigen antibody (HBsAb), and antibody to hepatitis B core antigen (anti-HBc). The risk of HBV transmission with kidney transplantation is a function of the serologic status of both donor and recipient. Knowledge of this risk is essential for the rational use of kidney allografts. HBsAg-positive donors are at high risk of transmitting HBV infection to their organ recipients, particularly if these donors are concurrently positive for hepatitis B e antigen (HBeAg). Kidneys from donors with isolated presence of HBsAb are unlikely to transmit HBV infection to their recipients. The risk of HBV transmission with the use of kidneys from IgG anti-HBc-positive, HBsAg-negative donors is low. Kidneys from donors negative for both HBcAg and anti-HBc are at low-to-negligible or no risk of transmitting HBV to their recipients. Under certain conditions, kidneys from HBV-infected donors can be safely used and thus prevent unnecessary discarding of organs. Kidneys from HBsAg-positive donors, who are negative for HBeAg, carry no risk or only minimal risk of transmitting HBV infection to their recipients if these recipients are immune to HBV or HBsAg-positive. However, the safety of these policies deserves further evaluation.