Abstract: The incidence of multiple primary lung cancers (MPLC), including synchronous multiple primary lung cancers (sMPLC) and metachronous multiple primary lung cancers (mMPLC), has been increasing in recent years due to the development of screenning, early detection techniques and the ageing population. A substantial percentage (0.2%-8%) of all newly diagnosed nonsmall cell lung cancer (NSCLC) cases are MPLCs. The distinction between multiple primary lung cancers and intrapulmonary metastases (IM) is based on pathological criteria, however, it is very difficult. Newly developed genetic methods are believed to be helpful for the distinction between MPLC and IM. Surgical treatment and stereotactic body radiation therapy are considered as effective methods in treating MPLC. Surgery options are varies from person to person due to different conditions of each patient. The prognosis of patients with MPLC, depended on the highest TNM stage tumor, is better than patients with IM.