At the present time, lung cancer is the leading cause of cancer-related death in males. Diagnostic difficulty makes detection complicated and this, in conjunction with the low survival rate, renders the disease a serious health problem. In-depth knowledge of associated risk factors is therefore called for, in order to prevent or at least reduce the appearance of lung cancer and to open new avenues of research. Although the disease has a multicausal aetiology, tobacco accounts for 85-90% of all cases. This paper reviews the current situation, dividing the risk factors, for study purposes, into two groups; intrinsic (non-modifiable) and extrinsic (modifiable).