The country was free of cholera until 2010, when UN peacekeepers dumped infected sewage into a river.
United Nations Secretary-General Ban Ki-moon on Tuesday expressed regret for sexual abuse by U.N. peacekeepers in Central African Republic and an outbreak of cholera in Haiti during his final address to the annual gathering of world leaders in New York.
Ban told the U.N. General Assembly that these two matters had "tarnished the reputation of the United Nations and, far worse, traumatized many people we serve." Ban will step down at the end of 2016 after serving two five-year terms.
The United Nations has promised to crack down on abuses after dozens of accusations of sexual abuse and exploitation by peacekeepers in Central African Republic, where U.N. troops assumed authority from African Union troops in September 2014.
The United Nations currently has 106,000 troops and police serving in 16 peacekeeping missions.
"The despicable acts of sexual exploitation and abuse committed by a number of U.N. peacekeepers and other personnel have compounded the suffering of people already caught up in armed conflict, and undermined the work done by so many others around the world," Ban said.
"Protectors must never become predators," he said.
In Haiti, Ban is working on a new response to an outbreak of cholera. The country was free of cholera until 2010, when U.N. peacekeepers dumped infected sewage into a river.
"I feel tremendous regret and sorrow at the profound suffering of Haitians affected by cholera," Ban said. "Let us work together to meet our obligations to the Haitian people."
He called it the "moral responsibility" of the U.N. to do so.
A 2011 study by the U.S. Centers for Disease Control and Prevention said U.N. peacekeepers from Nepal, where cholera is endemic, were the likely cause of the outbreak.
Since then, more than 9,000 people have died of the disease that causes uncontrollable diarrhea and 800,000 people have fallen ill, mostly in the first two years of the outbreak.
The United Nations has not legally accepted responsibility for the outbreak. An independent panel appointed by Ban issued a report in 2011 that did not determine conclusively how the cholera was introduced to Haiti.