Mucocutaneous lymph node syndrome has rarely been reported in the dental literature despite the orofacial features characteristic of the disease. A case is reported in which the cardinal signs were present: erythema of the oral mucosa, cervical lymphadenopathy, conjunctivitis, pyrexia, and desquamation of the skin of the hands and feet. In addition, hydrops of the gallbladder and cardiac disorder were also found. The patient may first seek treatment by the dental practitioner, by whom the diagnosis may be made. Attention is drawn to the possibility of cardiac abnormalities that may influence dental treatment.