Focal segmental glomerulosclerosis (FSGS) is a glomerular disease of varying severity. Most patients, however, develop end-stage renal failure within 10 years from clinical onset. In this retrospective study, the outcome of immunosuppressive treatment in 22 adult patients with biopsy-proven primary FSGS was evaluated. Eleven patients were treated with prednisone, azathioprine and chlorambucil (group A) and 11 with prednisone and pulse cyclophosphamide (group B). The nephrotic syndrome (NS) was found in 4 patients from the group A and in 3 patients from the group B, arterial hypertension in 8 and 9 patients, respectively. During the follow-up lasting about 50 months as the mean, 70% of the patients did not respond to the treatment and complete remission was obtained only in 3 patients from the group B. On the other hand, 7 patients progressed into CFR. Among them, 5 out of 7 patients with NS (4 from the group A) needed dialysis treatment or doubled their Pcr after a mean of 38 months. This study confirms poor outcome of immunosuppressive treatment in patients with FSGS. However, of the two forms of treatment used in the study, the response appeared to be better and more lasting with cyclophosphamide than with azathioprine and chlorambucil. Corticosteroids associated with pulse cyclophosphamide therapy seems to improve the chances of remission and to protect from renal dysfunction.