Despite the wide use of definitive chemoradiotherapy (CRT) for locally advanced esophageal adenocarcinoma, there is little evidence that CRT improves the survival of patients with esophageal adenocarcinoma compared with radiotherapy (RT) alone. Therefore, we retrospectively evaluated the outcome of patients with esophageal adenocarcinoma treated by CRT and RT alone. Patients were treated at the Gunma Prefectural Cancer Center (Ota, Japan) and the Gunma University Hospital (Maebashi, Japan). Patients provided written informed consent before treatment. Patients with distant metastases were excluded. CRT consisting of RT, nedaplatin, and 5-fluorouracil has been performed since 2002 when patients have adequate bone marrow, liver, and renal function. Between November 1993 and April 2006, 8 patients were treated by CRT and 12 were RT alone. The median follow-up period of surviving patients was 19 months. CRT group had a significantly higher complete response rate than those RT alone group (87% vs. 33%, P = 0.05). Of all patients, 2-year overall survival rate was 41% and the median survival time was 18 months. The 2-year overall survival of patients treated by CRT was 58%, significantly better than 24% of those with RT alone (P = 0.02). CRT can improve outcomes of patients with esophageal adenocarcinoma compared with RT alone.