A UN official, speaking on condition of anonymity because of the sensitivity of the issue, confirmed the release and said the UN staff member was abducted earlier yesterday in the capital Sanaa.
The official said the United Nations was seeking information on the UN driver kidnapped with him.
An Italian Foreign Ministry official, speaking on customary condition of anonymity, could not provide details on when the employee of the UN Development Program was kidnapped or about his release.
Yemen is engaged in a rocky political transition since longtime autocrat Ali Abdullah Saleh stepped down in 2012 following mass popular protests. Multiple armed groups across the country resist state authority.