We report four cases of double carcinoma of the esophagus and the lung. Case 1: a patient with synchronous double carcinoma of the esophagus and the lung underwent chemoradiotherapy (CRT) because of respiratory dysfunction. Case 2: a patient who was diagnosed with esophageal carcinoma after the surgery for lung carcinoma underwent CRT because of respiratory dysfunction. Case 3: a patient with synchronous double carcinoma underwent a two-stage operation. Case 4: a patient with synchronous double carcinoma underwent CRT at another hospital. To further treat the patients, we chose a two-stage operation. CRT is believed to be a feasible treatment in inoperable patients because patients 1 and 2 are alive 28 and 21 months after CRT, respectively. A two-stage operation is considered a suitably safe surgical procedure because no fatal postoperative complications occurred in cases 3 and 4.