To describe the histological frequencies, diagnostic methods, gender and age of lung cancer patients in a third level care hospital in western Mexico.A retrospective and descriptive study (2002 to 2005) was undertaken. From all reviewed cases, 242 patients had a diagnosis compatible with lung cancer. We analyzed the histological type, gender, age group, and diagnostic method.The histological type frequencies of lung cancer were as follows: 63.6% adenocarcinoma, 19.0% squamous cell carcinoma, 15.2% small cell carcinoma, and 2.2% large-cell carcinoma. Among these patients, a male-female ratio of 2:1 with a mean age of 63 years was found. Regarding the diagnostic methods followed, the most common included: transthoracic needle aspiration, bronchial biopsy, and bronchial washing.Adenocarcinoma was the most frequent histological type in the sample studied, an association between female gender and risk of developing adenocarcinoma was detected.