Russian Natural Resources Minister Yuri Trutnev said Rosneft made an "important" oil discovery in the Irkutsk Oblast near Mongolia, Russia's state-run news agency RIA Novosti reports.
"We can report today that we have opened the Sevastyanovo oil field, with reserves of over 1.1 billion barrels," he said. "This is a strategic deposit."
Trutnev said the amount of natural resources recovered from Russia in 2009 exceeded national expectations.
Russia extracted roughly 3.6 billion barrels of oil in 2009. Discoveries for 2009 eclipsed 4.5 billion barrels.
The Sevastyanovo oil field is located in Irkutsk Oblast near the route for the East Siberia-Pacific Ocean oil pipeline that links to Asian markets.
Trutnev made the announcement during a meeting with Russian Prime Minister Vladimir Putin.