Net profit in January-March quarter fell to Rs 2,549.08 crore from Rs 2,852.89 crore in the same period a year ago, the company said in a filing to the stock exchanges.
Sales were down to Rs 44,197.09 crore in the fourth quarter of 2015-16 fiscal from Rs 51,346.12 crore, a year-ago.
The company turned 6.22 million tons of crude oil into fuel, up from 6.11 million tons in the fourth quarter of 2014-15. Fuel sales also rose to 9.78 million tons from 8.69 million tons. Exports were however flat at 0.54 million tons.
The company said it earned USD 6.59 on turning every barrel of crude oil into fuel in 2015-16 as opposed to a gross refining margin of USD 3.62 a barrel in the previous fiscal.
It got fully compensated for the loss it makes on selling domestic cooking gas LPG and PDS kerosene at subsidised rates.
It received Rs 1,598.49 crore from the government as fuel subsidy and another Rs 198.01 crore as dole from upstream firms like ONGC.