The diagnostic approach in a patient with lung cancer should be oriented according to the mode of presentation of the disease. The first step includes history and clinical examination of the patient, and frontal and lateral chest X-ray, before histological typing of the tumor. The various diagnostic methods are selected according to localization of the mass in the thorax, and staging procedures are determined by the type of the tumor and the possible therapies available. The complexity of the problems surrounding patients with lung cancer mean that the general practitioner should seek the opinion of the chest specialist early rather than late in the pretherapeutic evaluation.