During the period 1981-1986, membranoproliferative glomerulonephritis was demonstrated in ten patients admitted to the Medical Department, Haukeland Hospital. At the time of the diagnosis all patients had proteinuria and hematuria, and six of them had renal failure. Seven patients exhibited nephrotic syndrome and three patients developed progressive renal failure during the observation period. Three patients died during the follow-up period. Four patients were treated with Cyclosporine A and corticosteroids. With this therapy the proteinuria disappeared in two of the patients with nephrotic syndrome. Immunosuppressive treatment may be tried if the disease shows signs of progression. We believe that some of these patients may benefit from cyclosporine A.