We present a unique case of a 63-year-old male patient with a squamous cell carcinoma of right upper lobe with paratracheal lymphadenopathy and symptoms of superior vena caval obstruction treated by radiotherapy, presented seven months later with symptoms of gastric outlet obstruction. Upper GI endoscopy and barium studies confirmed the diagnosis of functional gastric outlet obstruction. He was treated by an antecolic gastrojejunostomy. We postulate that the superior mediastinal mass with vagal nerve entrapment at the thoracic inlet resulted in symptoms of gastric outlet obstruction.