Lung cancer is the most common malignancy and the leading cause of cancer deaths in men and women. According to World Health Organization classification, lung carcinomas are morphologically classified into two main groups – small-cell and non-small-cell carcinomas, and the latter further into main subtypes – squamous cell carcinomas, adenocarcinomas and large cell carcinomas. Small-cell carcinomas have unique characteristics with a short doubling time, higher growth fractions, earlier development of widespread metastases and paraneoplastic syndrome. Although smoking remains the major cause of lung cancer, there is an increase in adenocarcinoma in never-smokers, especially women. It is recognized that risk of lung cancer declines after smoking cessation. The highest reduction is in small cell and squamous cell carcinomas, and the lowest reduction is seen in large cell cancer and adenocarcinomas. Despite the great progress made in the treatment of other cancers, the five-year survival of patients with lung cancer has remained poor, ranging from 7–18%. Complete resection of lung cancer is associated with longer survival remission but only about 25% patients are candidates for surgical treatment at the time of diagnosis. Accurate staging of the disease provides estimation of patient’s prognosis and treatment strategies. In recent years, the advent of successful molecular-targeted therapies for lung cancer have undergone a revolution in possible better prognosis for patients.