Guwahati Refinery is the India's first Public Sector Refinery serving the nation since 1962. Built with Rumanian assistance, the initial crude processing capacity at the time of commissioning was 0.75 MMTPA and the Refinery was designed to process indigenous Assam Crude.

The refining capacity was subsequently enhanced to 1.0 MMTPA. Due to dwindling supply of indigenous Assam Crude, Guwahati Refinery started processing Low Sulfur Imported Crude along with Assam Crude. The supply of LS imported crude to Guwahati Refinery is from Barauni Refinery via railway wagons.

The Refinery supplies various petroleum products to Northeastern India as well as beyond, upto Siliguri end through the Guwahati-Siliguri Pipeline, spanning 435 km. Most of the products of Guwahati Refinery are evacuated through pipeline and some quantity also through road transportation.

LPG, Naphtha, Motor Spirit (MS), Aviation Turbine Fuel, Superior Kerosene Oil, High Speed Diesel (HSD), Raw Petroleum Coke and Sulfur are the products of this Refinery. Auto fuels MS and HSD supplied by the refinery are of eco-friendly BS-IV grade as per statutory guidelines of Government of India.