59 sera of 10 immunosuppressed renal allograft recipients who experienced recurrent cytomegalovirus (CMV) infection were analyzed by enzyme-linked immunosorbent assay (ELISA) for CMV IgA antibodies and by the complement-fixation (CF) test. A significant rise of CF titer was evident 4–53 weeks post-transplantation. 9 patients produced CMV IgA in high titers at about the time the CF antibody rise was observed. 1 patient did not produce IgA antibodies to CMV. In 3 of the 9 patients, specific CMV IgA antibodies were detected before the rise in CF titer was demonstrated. CMV IgA antibodies were found to persist for as long as 66 weeks post-transplantation. The potential application of ELISA detection of CMV-specific IgA antibodies as an early indication of CMV infection in kidney transplant patients is discussed.