Wegener granulomatosis is more easily recognized as a distinct clinical entity than other vasculitides because the initial clinical features frequently include granulomatous vasculitis of the upper and lower respiratory tract and glomerulonephritis. Although the disease has been lethal in the past, prolonged survival and avoidance of end-stage kidney disease can now be expected when cyclophosphamide therapy is introduced early in the course. We report four children with Wegener granulomatosis in whom the initial clinical findings suggested Henoch-Schönlein purpura. In two of the patients Wegener granulomatosis was not recognized until after end-stage kidney disease had developed. The course in these patients emphasizes the need for attention to even scant evidence of inflammation of the upper or lower respiratory tract in patients with glomerulonephritis. Appropriate diagnostic studies may then lead to recognition of Wegener granulomatosis and the prompt institution of appropriate treatment.