Atkinson drove for the Subaru factory team in the WRC from 2004-08 and is currently leading the Asia Pacfic Rally in a Skoda.
He will now contest the remaining five rounds of the WRC as the number one driver for Mini, starting in Germany next weekend.
"I love the tarmac so it's great to know that three of the remaining five events are on the sealed surface and I hope to take full advantage of my past experiences of the remaining rallies this year," said Atkinson whose best WRC finishes were second places in Mexico and Argentina in 2008.
Atkinson, 32, has six podium finishes and 41 stage wins from 69 WRC starts. He won the Queensland Rally round of the Asia-Pacific series in May and came second in Malaysia last month to extend his lead to a massive 45 points.
He only needs a top-three finish in the next round in Japan next month to claim his first international rallying title without even having to contest the final round in China in October.