Wegener's granulomatosis is a vasculitis of the small blood vessels. Its causes are unknown. It is commonly associated with anti-neutrophile cytoplasm antibodies (ANCA). It is a multi-systemic autoimmune disorder characterized by necrotizing granulomatous inflammation, necrotizing tissue and various grades of vasculitis. The classic clinical model is a triad involving the upper respiratory tract, lungs, and kidneys. However, Wegener's granulomatosis is currently recognized as a highly polymorphic systemic illness which can affect any organ. Diagnosis is based on clinical manifestations including biopsies of lesions and positive tests for ANCA. The great majority of patients with ANCA associated vasculitis can control the illness with currently available immunosuppressant therapy. We report on four case of Wegener's granulomatosis in Colombia.