Zenker's diverticulum is a common anomaly in the elderly patient. Carcinoma in such a diverticulum is a rare but recognized complication of a posterior pharyngeal pulsion diverticulum. We present a case of a 67-year-old patient with a long-standing symptomatic Zenker's diverticulum. The diagnosis of the neoplasm was only achieved intraoperatively. The patient underwent a proximal esophageal resection with lymphadenectomy. Reconstruction was done with a microvascular free jejunal transplant. The postoperative course was uneventful. Wide oncologic surgical resection is the therapy of choice in cases of carcinoma in a Zenker's diverticulum.