He was received by Vice President Namadi Sambo on behalf of President Goodluck Jonathan at a brief ceremony held inside the Banquet Hall of the Presidential Villa.
Mimiko, who left the PDP in 2007 to contest against the late Dr Olusegun Agagu, was joined by members of his cabinet, LP lawmakers from the state in the National Assembly and 25 members of the state House of Assembly.
With him also was his wife, who was represented by his daughter, Eyitayo.
With Mr. Sambo to receive the defectors were Senate President David Mark; the PDP Deputy National Chairman, Uche Secondus and members of PDP National Working Committee.
In his speech, Mr. Mimiko said that his decision to join the PDP was taken in the overall interest of the people of Ondo and of the country at large.
The governor said that the decision enjoyed the endorsement of major stakeholders, including traditional and religious leaders, market men and women, trade unions, community and party leaders.
He said, “We feel compelled to join hands with the tendency that is aboard today in the PDP, led by a president that is as focused as he is patriotic.
“The PDP is a team that has demonstrated so much promise in its commitment to democracy without which the challenges facing our nation cannot be overcome.
“By providence, I am positioned to speak for the people of Ondo and our collaborators and admirers across the nation.
“And I do not have any doubt whatsoever in my mind that the interest of our people in Ondo, the South West Zone and that of Nigeria too, will be better served in the PDP in the evolving political configuration in our nation.
“It is in the light of the foregoing that I, Dr Olusegun Mimiko, today formally announce the decision of members of National Assembly from the LP in Ondo State, members of the LP in the Ondo State House of Assembly, members of the State Executive Council and indeed all those who share our aspirations, to join the PDP.
“I must confess that it surely was tempting and perhaps more fulfilling to continue as a national leader in our smaller, calmer and quite promising ocean represented by the Labour Party.
“But this decision to return to the PDP, we have taken in the overall interest of our people and our nation, and its democracy.”
The governor said his immediate target was to help the process of getting President Goodluck Jonathan re-elected.
He promised to spearhead the process by creating “a solid and robust platform of involvement in the re-election of the president”.
Responding, Mr. Sambo expressed happiness and excitement at Mr. Mimiko’s defection to the PDP, which he described as a homecoming.
He expressed hope that the governor’s return would help to resolve pending issues in the PDP in the South West.
Mr. Mimiko said, “You have come to raise the PDP to a higher level both in Ondo and in the South West.
“You have always been our partner in transformation and indeed your coming back home is deeply appreciated.
“We are confident that with your coming, the issues in the South West are being resolved by the PDP.”
The vice president assured Mr. Mimiko that all his entitlements, rights and privileges had been restored as a full PDP member.
Mr. Sambo, however, enjoined the governor to embrace and carry along every member of the party he had returned to meet.
He directed the PDP national vice chairman and the secretary to make arrangements for a rally in Akure where Mimiko and his teeming supporters would be formally received into the party.
Senate President, David Mark, said Mr. Mimiko had been a PDP member from the beginning, adding that he only went on self exile to the LP.
Mr. Mark, who chairs the PDP Re-integration Committee, said that the governor’s return would add value to the PDP in Ondo State and in the south west.
Mr. Mark advised the governor to return home and reconcile all members of the party in his state.
On his part, the PDP National Vice Chairman, Mr. Secondus, assured Mr. Mimiko and other defectors who might be interested in seeking elective offices in 2015 of a level-playing field.
On behalf of the national leadership of the party, Mr. Secondus added that those in need of waivers to contest would be granted.
He promised all potential aspirants in Ondo State of a level-playing field.
The high point of the occasion was the presentation of the PDP plaque by Mr. Sambo to the governor.