The Indo- Bangladesh plane of river Ganga, Meghna and Bbramhaputra is highly contaminated by environmental arsenic. The picture is worsen in West bengal, a state of republic of India. Over years common people are compelled to take contaminated subsoil water. Chronic exposure to arsenic contaminated water brings down their general health status with simultaneous development of arsenic induced diseases, including cancer. Reports available The problem is worsen in souther prtion of West Bengal where more than 9 districts are badly affected. The area and population of these arsenic affected districts of West Bengal are 38865 km2 and 42.7 millions respectively. people of those areas are suffering from myriad clinical problems and also cancers of lung, liver, bladder, skin and other organs of the body. This book is an priliminary effort to find out the molecular mechanism of arsenic induced cancer. genetic and epigenetic backgrounds are mainly tried to explored here so that in future research can be guided in this direction to resolve the issue.