The present investigation was carried out on the Tons river, a tributary of the river Ganga from March, 2012-February,2014 at four stations to study the seasonal change of physico-chemical factors and correlation matrix. The constituents monitored included water temperature, pH, transparency, total alkalinity, total hardness, dissolved oxygen, biological oxygen demand, free carbon dioxide, chemical oxygen demand. Through out the study period the water was good and acceptable for human's consumption and fish culture.