Democratic candidate Beto O'Rourke announced on Friday he was pulling out of his party's primary race after months of disappointing opinion polls and struggling to fund his campaign.
"Despite the difficulty of accepting it, it now seems clear to me that this campaign does not have the potential to progress successfully," O'Rourke wrote on the Media site.
With his withdrawal, 17 Democrats remain vying for their party's nomination.
O'Rourke, a former member of the House of Representatives, caused an uproar during his losing campaign to win a Senate seat in 2018, but failed to arouse enthusiasm about him in his party's primary, and remained below 2% in the rate of opinion polls conducted by the site "Real Clear Politics" .
Campaign director of communications Rob Friedlander told AFP he would "not be a candidate in the 2020 Senate election" for Texas.
US President Donald Trump was quick to comment sarcastically on O'Rourke's withdrawal. "No! Beto just pulled out of the presidential race while he was saying he was born," he said.