This case graphically illustrates the dental clinician's role in the diagnosis of Gardner's syndrome. Findings in the head and neck in this case led to discovery of the disease. Because of the high incidence of malignant transformation, surgery of the lower intestinal tract is done to remove any polypoid lesions. Normal-appearing tissue from which carcinoma might arise is also removed. Because of the usual occurrence of head and neck lesions in Gardner's syndrome, the clinician can make a major contribution in the diagnosis of this uncommon, but important, disease.