Jose Luis Rodriguez Zapatero, 50, announced Saturday he will not become the Socialist Party's candidate for the 2012 general election, El Pais reported.
"Now [the PP leaders] are going to have to come up with a platform, because all they have concentrated on is attacking me, saying that everything was Zapatero's fault," he said.
First elected in 2004, Zapatero has struggled to deal with a floundering economy, high unemployment and concerns of a bailout.
He denied his decision not to seek a third term had anything to do with the economic crisis or the fact that more than 4 million people remain jobless in Spain.
The Socialists are due to hold primaries this year to select a new secretary-general, who will become the party's candidate next year to run against PP leader Mariano Rajoy.