Oat cell carcinoma of the lung is an aggressive malignancy with a propensity for widespread dissemination. Surprisingly, spread of this tumor to the esophagus from adjacent lung is unusual. Although submucosal involvement has been noted occasionally, overt mucosal ulceration, to our knowledge, has not been demonstrated previously. Two patients with oat cell carcinoma developed painful dysphagia and mucosal ulceration from tumor infiltration into the esophagus.