He said the party dipped hands into the government's treasury to sponsor its 2015 campaign.
Obasanjo, who was president between 1999 and 2007 on the platform of the PDP, made this claim while speaking at a press conference on Thursday, May 10, 2018.
While speaking, he said his former party had 'directly or indirectly' used money from government treasury to run the 2015 elections which then-president, Goodluck Jonathan, eventually lost to President Muhammadu Buhari of the All Progressives Congress (APC) by over 2 million votes.
He said, "Concluding my point on corruption in politics particularly at the primary elections level, there must be strict control of campaign funding and transparent accounting by the Independent National Electoral Commission (INEC) of all funds contributed and all funds utilised by individuals and political parties for campaigns.
"I was shocked when an insider in the PDP told me that the amount of money the party used for 2015 elections would be in the neighbourhood of $3 billion. It was all directly or indirectly from the government treasury."
At the press conference, the former president announced that his Coalition for Nigeria Movement is adopting the African Democratic Congress (ADC) as its political platform to bring about desirable change in governance in the country.