A survey of the hepatitis B antigen (HBsAg) in Jerusalem blood donors revealed an overall prevalence of 0.75%, with a significant difference between males (0.90%) and females (0.38%). Analysis according to ethnic groups indicated that immigrants from North Africa had the highest prevalence (3.18%) and immigrants and tourists from North America and Europe the lowest (0.35%). Analysis according to volunteer, paid professional or family replacement categories indicated that a fourfold increase in the HBsAg prevalence for family donors (0.38 to 1.77%) coincided with the discontinuation of payment to professional donors and intensification of recruitment efforts toward volunteers and replacement donors. Case investigation of the HBsAg-positive donors within the family replacement group revealed that 24% were, in fact, commercial donors covertly engaged by the families of patients to fulfill replacement obligations. The present study illustrates how a community blood program which includes nonvoluntary donations, such as family replacement donations, incurs the risk of inadvertently introducting commercial blood donors into donor population. The findings support the premise that a 100% volunteer blood program is the most reliable guarantee for maintaining a blood supply from healthy donorswith a minimal risk of infectivity from hepatitis.