Addressing a PiS congress, Kaczynski said deputy president Beata Szydlo, 52, represented the party's best chance for "a big victory."
Szydlo, who is also a member of parliament, managed the campaign of Andrzej Duda, a conservative lawyer who staged an upset victory last month over popular incumbent Bronislaw Komorowski in presidential elections.
"If someone has to put together a team in the event of a win, it should be her," Kaczynski said, apparently renouncing the chance to head the next government if, as polls predict, PiS defeats the ruling centrist Civic Platform (PO) in the parliamentary vote.
Explaining his decision to let Szydlo take the reins in the event of an election win, he said: "Poland wants new faces and a new generation. Beata Szydlo is both young and experienced."
Also Read
With just four months to go to the election polls show PiS pulling ahead.
A survey published by CBOS institute on Thursday found the party enjoying a 31 percent to 25 percent lead over Prime Minister Ewa Kopacz's PO.
The anti-establishment movement of rock star Pawel Kukiz, who finished third in the presidential race, similarly ranked third in the CBOS poll with 19 percent.