18 patients with biopsy proven chronic proliferative glomerulonephritis have been studied, 10 of the 18 received daily subcutaneous injections of depo-heparin until death or for a period of at least 1 year. 8 of the 10 patients so treated demonstrated significant improvement in renal function as measured by serial determination of endogenous creatinine clearance, Addis count, protein permeability index, and renal biopsy. 1 patient with severely impaired function prior to heparin therapy did not improve, but renal function remained stable during the period of treatment. 8 of the 10 control patients were followed adequately for evaluation. Of these 8, 6 demonstrated progressive diminution of renal function, 4 expired in renal failure; in addition, 1 control patient followed too sporadically to include in the study is known to have died of renal failure.