Multiple endocrine neoplasia type IIb (MEN IIb) is a syndrome, part of which can involve neoplastic change in the thyroid and adrenal glands. It has unusual oro-facial manifestations including mucosal neuromata on the lips, cheeks and tongue. A child aged 3 years and 10 months presented with mucosal tags at the corners of the mouth, early eruption of permanent teeth, malocclusion and facial asymmetry. Biopsy of the excess mucosal tissue suggested a diagnosis of either MEN type IIb or neurofibromatosis. Genetic testing eventually confirmed MEN type IIb. The patient has been followed up regularly for 9 years. He has developed modular lesions on his tongue and irregular enlargement of his lower lip, but to date there have been no signs of tumour development. This report emphasizes the importance of thorough examination of the oral mucosa and follow-up of any abnormalities.