Gardner's syndrome is the association of multiple colonic polyps (familial adenomatous polyposis coli - FAP) with sebaceous cysts and jaw osteomas. The significance of this dominantly inherited condition to the dentist is that the colonic polyps usually undergo malignant change by the fourth decade and the extra-intestinal lesions may be apparent before those in the bowel. As such, early detection of multiple jaw osteomas and/or multiple sebaceous cysts (particularly on the scalp) may lead to appropriate further investigation and treatment which might be life saving. Diagnosis of this condition also has implications for other family members.