We describe three patients who became oliguric and uremic in the early posttransplantation period. Following treatment with pulse methylprednisolone, all had biopsy evidence of severe residual rejection that was predominantly vascular. T cells formed the bulk of the infiltrates. Subsequent treatment with the monoclonal antibody OKT3 was associated with an immediate diuresis and improvement in serum creatinine. Repeat renal biopsy, obtained in clinical remission, in two of the three patients, showed marked improvement in the vascular lesions. All three patients maintain normal renal function 9, 13, and 18 months later. We conclude that OKT3 was effective in reversing steroid-resistant rejection despite a predominantly vascular pattern of cellular infiltration not usually considered amenable to any antirejection therapy.