“It’s clearly not my time, I am going to end my presidential campaign,” he said in an interview on the MSNBC television network.
De Blasio vowed to “continue my work as mayor of New York City, and I’m going to keep speaking up for working people.”
“After several months of campaigning, I have reached a point where I feel I have contributed all I can to this primary,” he said in an email to supporters.
The announcement comes after de Blasio failed to qualify for the most recent televised debate among candidates as he struggled to get more than one percent in opinion polls.
His lengthy absence from the mayor’s office while on the campaign trail had also drawn widespread criticism, including from President Trump who reacted to the announcement by ridiculing his fellow New Yorker.
“Oh no, really big political news, perhaps the biggest story in years! Part time Mayor of New York City, @BilldeBlasio, who was polling at a solid ZERO but had tremendous room for growth, has shocking dropped out of the Presidential race,” Trump said on Twitter.
De Blasio is the seventh Democratic candidate to quit the race. His withdrawal narrows the overcrowded field to 19.
He is the second Democratic contender from New York to throw in the towel after Senator Kirsten Gillibrand ended her campaign late last month after also flatlining in the polls.
US congressman Seth Moulton, Washington Governor Jay Inslee and former Colorado governor John Hickenlooper also dropped out in August.
Former vice president Joe Biden is currently ahead in the polls on 28.8 percent, according to a poll average compiled by RealClearPolitics.
He is followed by the left-wing senators Elizabeth Warren on 18.3 percent and Bernie Sanders on 16.5 percent.
“Thank you @BilldeBlasio for making working families the center of your campaign. This is our moment to fight for an America that works for all of us — not just the people at the top. Let’s keep fighting,” Warren tweeted.
“Congratulations to @BilldeBlasio on running a campaign to lift up working people and push for bold solutions we need, including making health care a right through Medicare for All,” Sanders wrote on Twitter.
The next best placed in the polls are Pete Buttigieg, a mayor from Indiana, and California Senator Kamala Harris, but they are far behind the front three on less than six percent. (AFP)