The protocols of 852 patients with bronchogenic carcinoma (BC) were reviewed in order to establish its characteristics in the most extreme age groups in which it appears: group I, patients aged 40 years or younger (18 cases), and group II, patients aged 80 or older (19 cases). No differences were found in the relation men/women, time elapsed from the beginning of symptoms to diagnosis, staging and survival. The differentiating characters included the greater incidence of thoracic pain, microcytic carcinoma, surgery possibilities and therapeutic attitude in group I, and the predominance of squamous cell carcinoma in group II. The continuous and intense exposure to tobacco smoke is common to both groups.