Haiti's presidential runoff vote will take place on January 24, along with the second round of legislative elections, according to a presidential decree published.
The elections were originally scheduled for December 27 but were postponed indefinitely after vote fraud allegations, raising new fears for stability in the poorest country in the Americas.
In the October 25 first round to choose a successor to President Michel Martelly, the candidate he backed -- Jovenel Moise -- drew 32.8 percent of the vote against 25.3 percent for Jude Celestin.
A runoff had been due to go ahead on December 27 but was then cancelled after fraud allegations.
The first round and the subsequent lengthy and delayed vote count were marked by street protests alleging official corruption.
Celestin refused to campaign until an independent electoral commission was set up. The commission found in its report, released Sunday, that work by the government's Electoral Board was sloppy and led to many irregularities.
The October presidential election was the latest attempt in the Caribbean nation to shed chronic political instability and work toward development.
After being mired for years in a political crisis that kept any elections from being held, Haiti went on an electoral marathon in 2015, holding legislative, municipal and presidential polls.
Haiti is still struggling to recover from a devastating 2010 earthquake that killed more than 250,000 people and crippled the nation's infrastructure.
Since the end of the Duvalier dictatorship in 1986, Haiti has been jolted by coups and contested elections that have further undermined the fragile economy.