“While we are on the right side, this year, we will not be the winning side,” he told supporters in Miami on Tuesday night.
The 44-year-old first term senator warned his voters: “America is in the middle of a real political storm, a real tsunami and we should have seen this coming.”
Rubio's family comforted him with a group hug as he announced he was suspending his campaign.
His supporters cheered for him to fight to the convention, but Rubio responded saying: “Look, people are angry.”
Trump won in key primary states including Florida, North Carolina and Illinois. Ohio Governor John Kasich won in his state.
On the Democratic side, Hillary Clinton swept Bernie Sanders and used her victory speech to take aim at Trump.
“Our commander-in-chief has to be able to defend or country, not embarrass it,” she said.