BACKGROUND Large cell neuroendocrine carcinoma is a recently recognized histologic entity whose clinical features and optimal treatment have not yet been well defined and are still being assessed. We report our retrospective assessment of cases of large cell neuroendocrine carcinoma observed from 1989 to 1999 in terms of survival. METHODS Cases of large cell neuroendocrine carcinoma diagnosed between 1989 and 1999 were reassessed retrospectively according to the World Health Organization classification. The clinical outcome and pathologic features of all cases are described. Survival rates of patients with large cell neuroendocrine carcinoma are compared with those patients with small cell lung cancer treated in the same period. RESULTS Patients were 41 men and 7 women with an average age of 63.7 years. Twenty-nine patients (60.4%) had pathologic stage I disease, 11 patients (22.9%) had pathologic stage II disease, and 7 patients (14.6%) had pathologic stage IIIA disease. One patient (2.1%) had pathologic stage IIIB disease. No patient underwent induction chemotherapy. Two patients underwent adjuvant chemotherapy and 2 underwent mediastinal radiotherapy for N2. No death was reported in the perioperative period. The median follow-up was 5 years. The actuarial survival for the entire group was 60.4% at 1 year, 27.5% at 3 years, and 21.2% at 5 years. The actuarial survival of accurately staged, stage I patients at 5 years was 27%. CONCLUSIONS The findings suggest that treating large cell neuroendocrine carcinoma by means of applying treatment for nonsmall cell lung cancer leads to a prognosis that is worse than that for nonsmall cell lung cancer, even in terms of low pathologic stages.