Three patients were treated with combined amphotericin B and rabbit anticryptococcal antibody in the 1960s. Rabbit antibody was administered intravenously and was well tolerated. For each patient, administration of rabbit antibody resulted in the appearance of serum Cryptococcus neoformans agglutinins. For two patients the administration of rabbit antibody resulted in negative serum latex tests for cryptococcal antigen. This limited experience with adjunctive antibody therapy provides valuable precedents if antibody therapy is used again for treatment of human cryptococcosis.