Background: Lupus nephritis, especially diffuse proliferative type is one of the potentially life threatening disabling consequences of SLE that needs intensive and invasive treatment. As there is not enough information available about the results of Intravenous Cyclophamide (IVC) therapy on these patients in our country, this study was performed from 1997 to 2002 in Esfahan Azzahra Hospital. Materials and Methods: In this semi-experimental study 14 hospitalized patients with Diffuse Proliferative Glomerulonephritis (DPGN) were treated with IVC, and the efficacy of IVC was investigated by evaluation of urine sediment, serum urea, creatinin, and urinary excretion of creatinin and protein. The results were evaluated after 6,12 and 24 months of IVC therapy again. All of the data were analyzed by paired t-test and Chi - square test. Results: 3 patients were excluded and 14 patients were studied. Partial remission was seen in 5 patients (33.4%) after 6 months, and in one patient (7.1%) after 12 months of IVC therapy. There was not any cases of partial remission after 24 months of treatment. The rate of complete remission in 6th, 12th and 24th months of study were 14.3%, 28.6% and 28.6%. The cumulative frequency of complete remission cases in 6th, 12th and 24th months of study were 14.3%, 42.9% and 71.4%. In general, only 3 (21.4%) cases continued to have proteinuria in the range of nephrotic syndrome after 24 months of treatment. The average interval to achieve partial remission was 7.7 2.9 months and for complete remission was 15.6 7.59 months. Conclusion: Most cases with diffuse proliferative lupus nephritis achieved complete remission after 2 years (71.4%) of IVC therapy. So we recommend this treatment for all patients with lupus induced diffuse proliferative glumerolonephritis.