Adenosquamous carcinoma of the lung is a rare disease. The biological behavior and clinicopathologic characteristics of this tumor have not been well described. In this study, we retrospectively evaluated 13 patients with adenosquamous carcinoma of the lung diagnosed at our center between January 2001 and May 2004. There were 12 males and 1 female whose ages ranged from 45 to 69 years, with a mean age of 55.9 years. Ten patients were smoker. The most frequent symptoms were chest pain and cough. Bronchoscopic examination detected that tumor was centrally located in four cases and was peripherally located in nine cases. Preoperative pathological diagnosis was squamous cell carcinoma in eight patients, non-small cell lung carcinoma in four patients and adenocarcinoma in one patient. One patient was in pathological stage IA, three patients in stage IB, one patient in stage IIA, two patients in stage IIB, five patients in stage IIIA, and one patient in stage IIIB. Twelve patients underwent resection (six, lobectomy; five, pneumonectomy; one, bilobectomy). Five of 12 patients received adjuvant therapy. Five patients died of disease within 3 and 21 months. Seven patients have had survival time between 9 and 31 months.