A double blinded clinical trial was conducted in which the efficacy and safety of pulse methylprednisolone (400 mg/day) was compared with oral prednisolone (50 mg/day), a control drug for a period of 3 months. One-hundred and two (102) patients were enrolled in the study, of which 91 patients were determined as eligible for analysis of efficacy. Patients on pulse methylprednisolone had more favorable response to therapy with regard to laboratory value changes from baseline such as CH50 and anti-DNA antibody titers. In terms of anti-DNA antibodies, a significant difference was detected at one week after treatment. With regard to time course changes in laboratory values, CH50 at one and two weeks after treatment showed a significantly higher elevation in the pulse methylprednisolone group than in the control group. There was no significant difference noted in incidence of adverse reactions between both treatment groups. No serious adverse reaction was encountered in the pulse methylprednisolone group. The physician's assessment of final global improvement significantly favored the pulse methylprednisolone-treated group. The above results suggest that the pulse therapy with methylprednisolone leads to more rapid onset of drug effect than the conventional oral prednisolone in the treatment of lupus nephritis.