Although Wegener's granulomatosis is a relatively well defined clinical-pathologic entity, there are few long-term reports of large numbers of patients followed at a single institution. This has hindered appreciation of the diagnosis, management, and course of the syndrome. We report an analysis of 18 patients followed at one medical center. Delay in treatment can be obviated by awareness of this potential diagnosis in any patient with combined respiratory and renal manifestations. Biopsy of involved respiratory tissue yields a high probability of establishing a specific diagnosis, while biopsy of renal tissue often provides confirmatory evidence of a vasculitic disease process. The initial degree of renal involvement as manifested by serum creatinine, proteinuria, and light microscopic morphology correlates well with eventual prognosis. The availability of modern immunosuppressive therapy and of modalities to treat end-stage renal disease appears to have greatly influenced the course of the disease.