Anti-lymphocyte antibodies in sera of multitransfused dialysis patients can be readily identified using the indirect immunoperoxidase method. Concordance between the microlymphocytotoxicity and immunoperoxidase methods was obtained in 61/66 paired specimens. The sensitivity of the immunoperoxidase antiglobulin technic is approximately that of the microlymphocytotoxicity method. This test may be used for lymphocyte crossmatching prior to renal transplantation.