Reliance Industries, which in western India operates the world's biggest refining complex, said net profit was 54.9 billion rupees ($898 million) in the three months to Sept. 30, compared with 54.09 billion rupees in the same period a year earlier.
The mean Reliance Industries earnings estimate of 11 analysts surveyed was for 54.9 billion rupees.
Reliance Industries, controlled by India's richest man, Mukesh Ambani, posted an average gross refining margin of $7.7 per barrel for the quarter, down from $9.5 a year earlier.
Reliance Industries's growth is tied to its offshore Krishna Godavari D6 field, which the government expects to supply a significant portion of the country's gas.
The government may appoint an international expert to investigate a decline in output from the field, the oil secretary said last month.
The decline, since April 2010, has led to supply cuts for electricity generation and other sectors.
($1 = 61.1350 Indian rupees)