This study was done to determine whether intravenous methylprednisolone therapy given concomitantly with low-dose daily, oral prednisone would be as effective as high-dose daily prednisone in the treatment of patients with active systemic lupus erythematosus (SLE) nephritis. Thirteen patients with active SLE nephritis were started on 2 mg/kg prednisone per day, considered the high prednisone phase. Therapy was continued until remission was achieved. Prednisone administration was then tapered to less than 0.5 but more than 0.2 mg/kg per day. On later relapse, these patients received three doses of methylprednisolone (20 mg/kg per dose) on alternate days and continued on the same daily dose of prednisone (less than 0.5 greater than 0.2 mg/kg per day) prior to pulse therapy; this was the methylprednisolone phase. The 13 patients were studied in both phases, serving as their own controls. After 1 month of therapy, no significant differences were observed between treatment phases as to improvement in clinical and laboratory findings. A significant increase in the serum concentration of C3 and C4 was seen both in the high-dose prednisone and methylprednisolone phases, while the serum concentration of anti-ds DNA antibody significantly decreased. Methylprednisolone therapy seems as effective as high-dose prednisone in patients with relapse of SLE nephritis. Because side effects are minimal, methylprednisolone administration may be tried as the therapy of choice for these patients.