A 51-year-old engineer was admitted with progressive lower back pain which had started 4 months before. We found an elevated ESR and anemia. Chest X-ray showed bilateral polycyclic thickening of the pleura, and abdominal CT examination revealed a paraaortic tumorous lesion and a solid kidney tumor with a diameter of 5 cm on the left side. During the course of the disease we also observed an infiltration in the apex of the upper lobe of the left lung. Histological examination showed fibrotic tissue typical of Ormond's disease in the kidney tumor as well as in the pulmonary infiltrate. We diagnosed a systemic form of retroperitoneal fibrosis. Treatment with cyclophosphamide (combined with prednisone during the first 4 months) resulted in complete remission of the disease.