An indirect peroxidase antibody to membrane antigen (IPAMA) technique was applied for determination of immunoglobulin G (IgG) antibody to human cytomegalovirus (CMV). The antigen consisted of air-dried, CMV-infected cells. The results were compared with those obtained with the CMV complement-fixation (CF) test. Comparison of titers obtained by IPAMA with those obtained by CF for sera of 48 healthy adults and 7 CMV patients showed good agreement between the tests. No cross-reactivity with other herpesviruses was observed. There was no problem of nonspecific cytoplasmic reaction with Fc receptors for IgG, even at low serum dilutions. The IPAMA technique appears to be reliable, is easily and rapidly performed, and is recommended as a routine test for serological diagnosis of CMV infections as well as for screening the general population.