Kidney transplantation between ABO incompatible pairs, contraindicated because of a high incidence of hyperacute rejection episodes, has become feasible after provisional removal of anti-A or anti-B antibody from recipient canidates. Initially, a total of 54 patients were scheduled to be transplanted with ABO incompatible kidneys after removal of anti-A or anti-B antibody by immunoadsorption, using A or B antigen expressing trisaccharide immobilized on silica beads. Levels of anti-A and/or anti-B antibody (-ies) were negative (below less than X8 dilution) after three to four immunoadsorption treatments, and, thereafter, kidneys were successfully transplanted in 47 patients (incompatibility in A:21, B:25, AB:1). However, in four patients, anaphylactoid reaction occurred immediately after initiation of immunoadsorption, and double filtration plasmapheresis (DFPP) took place. Kidney transplantation was cancelled in three patients because of rebound to high level of anti-A or anti-B antibody, or appearance of T cell antibody after immunoadsorption.