The move sends a clear signal Rosneft is keen to profit from its own trading after selling oil for years via international energy companies such as BP (BP.L) or trading houses such as Vitol and Gunvor.
Run by Igor Sechin, a close ally of President Vladimir Putin, the world's top listed oil producer by output took over TNK-BP in a $55 billion deal this year, continuing to snap up domestic and foreign assets in a move to become a global energy major.
Morgan Stanley agreed to sell the majority of its global physical oil trading operations to state-controlled Rosneft, becoming the latest Wall Street firm to dispose of a major part of its commodity business.
Deutsche Bank announced two weeks ago that it was also largely exiting commodities trading, while JPMorgan is selling its physical trading operations.
"At the moment, we are focused on this deal completion and the asset's maximum possible integration into the Rosneft structure," the company told Reuters in an emailed reply to a question about its future trading acquisition strategy.
Rosneft, which pumps around 40 percent of Russia's oil output of 10.6 million barrels a day, said the roughly 100 traders and 180 back-office personnel joining under the deal would stay in their current cities - London, New York and Singapore.
Still, Rosneft's trading desks will still be dwarfed by BP's (BP.L) trading operation of over 3,000 people. It is unclear whether any core Rosneft staff will join new hires abroad later.
Rosneft, which already has an oil trading division in Geneva helping to supply its refining assets in Europe, did not gave a breakdown of how staff will be internationally split. Neither Rosneft nor Morgan Stanley disclosed the price.
On Friday, it said that the deal will become "a platform to create a first class international marketing and sales structure," which will centralize Rosneft and third parties oil and products' flows aiming to raise sales effectiveness.
The deal is the latest push by Rosneft into North America and follows an agreement with ExxonMobil (XOM.N) in 2011 which gave the state-run company access to some projects, such as the Cardium tight oil project in Canada, West Texas unconventional exploration and deepwater exploration in Gulf of Mexico in the United States.
The purchase will not include Morgan Stanley's oil storage, pipeline and terminals firm, TransMontaigne Inc., which may help avoid significant scrutiny of the deal in Washington.
Reporting by Katya Golubkova; Editing by William Hardy