Trypanosoma cruzi, a parasite that causes Chagas' disease, is endemic in parts of Mexico, South America, and Central America. Transmission of T. cruzi infection by solid organ transplantation has been reported in Latin America and recently in the United States. To determine the prevalence of T. cruzi antibodies in Southern California organ donors, 404 samples from deceased organ donors between May 2002 to April 2004 were screened using a qualitative enzyme-linked immunosorbent assay (EIA) and confirmed with an immunofluorescence assay (IFA) available through the Centers for Disease Control (CDC). Six donors were initially reactive by EIA. Three donors were repeatedly reactive after repeat testing and were sent to the CDC for confirmation. One donor (0.25%) had an IFA-confirmed reactivity to anti-T. cruzi antibodies. In areas where there is a high number of immigrants from T. cruzi endemic countries, screening for anti-T. cruzi donor antibodies may be beneficial.