A high incidence of synchronous esophageal or gastric carcinoma in preoperative patients with carcinoma of the oral cavity was reported. Esophageal carcinoma was found in seven out of 56 patients (12.5%) and gastric cancer in five patients (8.9%) by videoendoscopy aided with lugol staining in the esophagus and indigocarmine solution in the stomach, although all patients were completely asymptomatic for these lesions. All patients were male, regular drinkers and heavy smokers. The depth of invasion of such tumors was limited to either mucosa or submucosa. Those esophageal and gastric lesions beside the primary oral cancers were positive for p53 protein by immunohistochemistry. Careful preoperative evaluation of not only the esophagus but also the stomach should be a routine procedure in patients with carcinoma of the oral cavity.