In this prospective randomized trial, we compared the effects of cyclosporine- and cyclophosphamide-based treatment regimens in patients with idiopathic membranous nephropathy. Twenty-eight patients were randomized to receive treatment with one of the three therapeutic regimens: cyclosporine with methylprednisolone, cyclophosphamide with methylprednisolone or lisinopril (control). Renal function and nephrotic syndrome parameters were determined at baseline and during a 9-month treatment period. At the end of the study period, renal function improved significantly in the cyclophosphamide and deteriorated significantly in the cyclosporine group. Serum albumin levels increased significantly in the cyclosporine and cyclophosphamide group. Total cholesterol levels and proteinuria were significantly reduced in all groups. In the comparison between the groups, serum albumin levels were significantly lower in the control group and there were no differences in the rest of the studied parameters at the end of the study. Six patients from the cyclosporine group (1/10 complete and 5/10 partial), all cyclophosphamide-treated (4/8 complete and 4/8 partial) and all 10 lisinopril-treated patients (10/10 partial) were on remission at the end of the study. In conclusion, cyclosporine-based regimens are not inferior to cyclophosphamide-based regimens. Cyclophosphamide is associated with more complete remissions after 9 months of treatment. Lisinopril is associated with a significant proteinuria reduction and without inducing any complete remissions.