"After much thought I have decided to end my campaign for president today," Chafee said at the Democratic National Committee's Forum on Women's Leadership in Washington, D.C.
With his announcement, now only three Democratic contenders remain: Hillary Clinton, Bernie Sanders and Martin O'Malley.
Chafee, who began his political career as a Republican before becoming an independent and finally a Democrat, had struggled so far to raise money or gain any traction in the polls. According to the most recent ABC News/Washington Post poll, his support was less than one-half of 1 percent, and last quarter he raised just over $11,000 from donors. Before the first Democratic debate, however, he told ABC News he thought he could last on his shoestring budget until the Iowa caucuses.
"I pretty much made the decision last weekend," Chafee said after his remarks at the DNC Women's Forum. "I'm a deliberative person. I always take my time with decisions."
He had also previously served as a U.S. senator and the mayor of Warwick, Rhode Island, and on the campaign trail talked most about his voting record and accomplishments in Rhode Island. During his campaign announcement, he made headlines for advocating to switch to the metric system, saying that the U.S. should “join the rest of the world and go metric.”
Chafee ended his remarks saying, "Thank you and 'Go Democrats' in 2016!" He said he has no plans to endorse a candidate at the moment, but will “definitely” support the nominee.
DNC Chairwoman Debbie Wasserman Schultz thanked the governor for his public service and called him a "class act."
ABC News' Ryan Struyk and Alana Abramson contributed to this report.
Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here.