It is the first time in decades that an incumbent French president has not sought re-election.
Hollande is the most unpopular president on record.
“I am aware today of the risk that going down a route that would not gather sufficient support would entail, so I have decided not to be a candidate in the presidential election,” a sombre-looking Hollande said in a televised address.
All recent polls have predicted that neither Hollande nor any other Socialist candidate would make it past the first round of the election.
They predict a run-off battle between centre-right candidate Francois Fillon and the leader of the far-right National Front, Marine Le Pen.
The left is deeply divided as it approaches the election.
Several other Socialists, including former economy minister Arnaud Montebourg, have said that they will take part in the party’s primaries in January.
Another of Hollande’s former ministers, Emmanuel Macron, and leftist firebrand Jean-Luc Melenchon have said they will run in the presidential election but without taking part in the primaries.
There has been tension between Hollande and his prime minister Manuel Valls, who raised the possibility in a weekend interview that he might run in the primaries against his boss.
Hollande beat conservative incumbent Nicolas Sarkozy in an election in May 2012 after a classic left-wing campaign in which he targeted big business and pledged to raise taxes for high earners.
But his popularity soon began to decline with a perceived lack of leadership and flip-flops on key issues, particularly tax reform, which dismayed many on the left.
His popularity has been undermined by stubbornly high unemployment and anaemic economic growth.
Grassroots supporters were further alienated by a pro-business switch in 2014, a wavering over security reforms, and by labour laws that brought thousands out onto the streets in protests early this year.
Hollande’s image was also hit by a series of communication mis-steps, including a very public split with his ex-partner Valerie Trierweiler and pictures of him going to visit his new partner on a scooter.
The last straw for some of his closest supporters was the publication of a book by two Le Monde journalists in October.
In interviews with them, Hollande criticised several of his allies and others from judges to footballers, in comments that were widely criticised as indiscreet and ill-befitting a president.
He also disclosed that French secret services had carried out four targeted killings on his orders.
Le Monde wrote in an editorial earlier that the Socialists risked tearing themselves apart, further diminishing their chances in next year’s presidential and parliamentary elections.
“The person who is most responsible is François Hollande, who has not given a meaning to his time in office, occupied the job with authority or imposed himself as the legitimate candidate for his party,” it said. “The longer he keeps up the uncertainty, the worse the confusion will get.”
And there could be more bad news to come.
Hollande’s embittered former aide Aquilino Morelle has announced a tell-all book to be published around the same time as the primary about the president’s first few years in power.
Its title? The Abdication.
