Peltz said that the company had wasted more than $100 million to keep him off the board, despite him having no intention of replacing any board member or Chief Executive David Taylor, and that the vote would be close.
"This proxy fight is probably the dumbest thing I've ever been involved in," Peltz told CNBC on Friday.
One of the best known activist investors in corporate America, Peltz has amassed a $3.5 billion stake in P&G through his firm Trian Fund Management.
He says he wants the company to improve shareholder returns by speeding up a transformation begun in 2014 and further streamlining its operations, moves he hopes he can push with a board seat.
He has also repeatedly said that the company has a "suffocating bureaucracy" that is stalling progress and that reorganizing the company into three global business units would reduce complexity.
"P&G has lost its soul," Peltz said.
With a $235 billion market capitalization, the Oct. 10 vote makes Procter & Gamble the biggest ever firm to face a proxy fight - where two competing groups battle for the shareholder votes needed to control and change companies. P&G in a statement on Friday reiterated its stance that Peltz wasn't a right fit for the board, particularly at this time as the company was in the final stages of its transformation.
"Peltz's timing is late to P&G's turnaround," the company said in the statement.
(Reporting by Siddharth Cavale in Bengaluru)
By Siddharth Cavale