Fifteen patients with vasculitis and renal manifestations have been analyzed. All patients had renal manifestation of vasculitis. Renal biopsy was performed in 13 patients: 6 patients had microscopic polyangiitis, 4 Wegener's granulomatosis, 2 microscopic polyangiitis limited to the kidneys and 3 polyarteritis nodosa. Renal biopsy was not performed in 2 patients. One patient had renal insufficiency and small kidneys and one patient had polyarteritis nodosa. The diagnosis of the polyarteritis nodosa in this last patient was made because of other clinical and laboratory data. Pauci-immune type of glomerulonephritis was found in 11 patients. The crescents, usually cellular, fibrocellular and rarely fibrotic, were present in 20-100% glomeruli. Renal insufficiency at baseline was present in 14 patients (creatinine 215-1224 micromol/L). Only one patient had borderline renal function when the diagnosis of vasculitis was made (creatinine 115 micromol/L). All patients with glomerulonephritis were treated with glucocorticosteroids and cyclophosphamide. Five patients with pulmonary manifestations of disease or advanced renal failure also were treated with plasmapheresis. Eight patients were treated by hemodyalisis. The complete or partial remission in the first year of the follow-up was reached in 9 patients, and 5 patients were treated by chronic dialysis due to chronic renal failure. One patient with Wegener's granulomatosis died after he developed toxic megacolon and postoperative sepsis.