Cancer risks associated with the use of smokeless tobacco (SLT) products worldwide vary drastically. There is a critical need to better understand SLT induced carcinogenesis, and the chemical constituents and/or product characteristics that drive the risk of cancer development. India is one of the largest producers and consumers of tobacco, most of it in the form of SLT. The goal of our project is to investigate the relationship between carcinogen content in SLT products and its impact on relevant exposures to these carcinogens and the risk of OHNC among users. Concurrently the project also aims at building capacity for a sustainable tobacco carcinogenesis research program in India. This project is funded by the National Institute of Health (NIH), USA (Grant No. R01-TW010651).