Clinton, who is popular among many Haitians for using the threat of U.S. force to oust a dictatorship in 1994, visited Haiti as president in 1995.
In an interview on "World News" Wednesday, Clinton said he thought the disaster in Haiti, affecting more than 3 million people, may be one of the most devastating tragedies ever to hit the United Nations.
"Our U.N. hotel, as you know, [was] five stories [and] completely collapsed." Clinton said.
At least 16 U.N. employees, including the chief of the U.N. mission in Haiti, Hedi Annabi, have died, with at least 56 more injured, a U.N. spokesman said. Nearly 100 more are unaccounted for.
"It's highly likely to be the highest mortality count we've ever had," Clinton said.
Officials speculate that up to 50,000 people may have died across the island.
To learn more about ways that you can help the victims of Haiti's earthquake, click HERE.
ABC News' Yunji de Nies and Kristina Wong contributed to this story.