Atiku scored 1532 votes to defeat his closest opponent, Aminu Tambuwal, who polled 693 votes.
Tunde Bakare, serving overseer of the Latter Rain Assembly (LRA), says former vice-president Atiku Abubakar will give President Muhammadu Buhari a tough fight for the presidency during the 2019 elections.
"You have turned around our economy from a mono economy and one thing that we all can not forget is that within a short time, Nigeria was out of recession". "We are only working with you (Mr Abubakar) to victory".
Other contestants were former Governor of Plateau State, Jonah Jang, 19 votes; former President of the Senate, David Mark, 35; former Minister of Special Duties and Intergovernmental Relations, Kabiru Taminu Turaki, 65; and former Governor of Jigawa State, Sule Lamido, 96. It is not a one man's job, it is a collective responsibility and I am prepared to listen to you, to take your advice, consult with you, work with you and together, we'll succeed and after we succeed, we shall all be partners in that success.
"He has the power of incumbency and he will do his best to win the election, but Atiku is not going to take No for an answer when the two forces collide in the election".
"I can not do it alone, I need your support, your assistance, I need your understanding and I need your participation".
Mr Abubakar, who spoke without a prepared script, commended his challengers, saying they showed "a sense of unity, a sense of objective and a sense of commitment".
"I stand here on behalf of your governors to affirm that you have discharged your responsibility creditably".
He described President Muhammadu Buhari as clueless, adding that the PDP can not afford to fail at the general election.
"We invite the whole world to note that the PDP conducted its presidential primary and a clear victor, Atiku Abubakar, emerged, without any form of disagreements or reliance on heavy security".
But next year's presidential race appears to have tightened in recent months with the APC hit by a wave of defections over Buhari's leadership style.