Russia's energy giant Gazprom has signed a $2.5bn (£1.53bn) deal with Nigeria's state operated NNPC, to invest in a new joint venture.
The new firm, to be called Nigaz, is set to build refineries, pipelines and gas power stations in Nigeria.
Analysts say the move could further strengthen Russia's role in supplying natural gas to Europe.
The agreement comes during a four-day African tour by Russian President Dmitry Medvedev.
As well as forming Nigaz, Russia is keen on developing a trans-African pipeline to transport Nigerian gas to Europe.