Although the mouth is often involved in Wegener granulomatosis, oral lesions as the initial sign are rare. This case report documents the importance of considering Wegener granulomatosis in patients with unique oral lesions. The most common lesion is a friable-granular-hyperplastic gingivitis associated with alveolar resorption and tooth mobility. The disease may remain localized to the mouth for several weeks or months before multiorgan involvement occurs. Gingival enlargement is a direct manifestation of Wegener granulomatosis, and it may be pathognomonic. Failure to recognize the clinical lesions can result in delayed diagnosis and treatment, with potentially fatal results.