Bronchocentric granulomatosis is a chronic pulmonary disease treated with short-term therapy with corticosteroids, and the disease has an excellent prognosis. We describe a patient, and review an additional case from the literature, in whom bronchocentric granulomatosis was accompanied by glomerulonephritis. A misdiagnosis of Wegener's granulomatosis was made, and therapy with cyclophosphamide was either considered or given in each of these cases. We emphasize the need for careful histopathologic evaluation of open lung biopsies in patients suspected of having Wegener's granulomatosis in order to rule out the possibility of bronchocentric granulomatosis with concurrent renal disease, and thus avoid the unnecessary use of cytotoxic agents.