Objective. - To provide physicians and other transfusion medicine professionals with a current consensus on infectious disease testing for blood transfusions. Participants. - A nonfederal, nonadvocate, 12-member consensus panel representing the fields of hematology, infectious disease, transfusion medicine, epidemiology, and biostatistics and a public representative. In addition, 23 experts in hematology, cardiology, transfusion medicine, infectious disease, and epidemiology presented data to the consensus panel and a conference audience of 450. Evidence. - The literature was searched through MEDLINE and an extensive bibliography of references was provided to the panel and the conference audience. Experts prepared abstracts with relevant citations from the literature. Scientific evidence was given precedence over clinical anecdotal experience. Consensus. - The panel, answering predefined consensus questions, developed their conclusions based on the scientific evidence presented in open forum and the scientific literature. Consensus Statement. - The panel composed a draft statement that was read in its entirety and circulated to the experts and the audience for comment. Thereafter, the panel resolved conflicting recommendations and released a revised statement at the end of the conference. The panel finalized the revisions within a few weeks after the conference. Conclusions. - The serum alanine aminotransferase test should be discontinued as a surrogate marker for blood donors likely to transmit posttransfusion non-A, non-B hepatitis infection since specific hepatitis C antibody testing has eliminated more than 85% of these cases. Antibody to hepatitis B core antigen testing should continue as it may prevent some cases of posttransfusion hepatitis B; it may also act as a surrogate marker for human immunodeficiency virus (HIV) infection in donors and may prevent a small number of cases of transfusion-transmitted HIV infection. Syphilis testing should continue until adequate data can determine its effect on the rarity of transfusion-transmitted syphilis. Vigilant public health surveillance is critical in responding to emerging infectious disease threats to the blood supply.