UN staffers Annetta Flanigan and Shqipe Hebibi and Filipino diplomat Angelito Nayan were released early on Tuesday morning, according to a police official.
“They are out,” said UN spokesman Manoel de Almeida e Silva.
There are reports they were released after a rescue operation, in which one kidnapper was killed and four others wounded.
The trio, who had been helping oversee Afghanistan’s first democratic elections, were snatched from busy lunchtime traffic in downtown Kabul on October 28 by armed men who later claimed to be a Taliban splinter group.
It was the first such abduction in the Afghan capital since the Taliban fell three years ago.
All three workers are now at a Nato field hospital in Kabul, receiving medical examinations but reportedly appear to be well and unharmed.
Relieved Philippine officials said they had been told of the release, and praised the work of Afghan and UN officials during the crisis.
“We appreciate the efforts of the UN as well as of the Afghan government,” said Silvestre Afable, a spokesman for President Gloria Arroyo, adding that no ransom had been paid for the freedom of the three.
The hostages’ release comes a day after US and Afghan forces raided three houses in southwest Kabul in an effort to locate the trio.
At least 10 people were detained during the raid for questioning by Afghan intelligence, and most have been released after questioning.
Taliban splinter group Jaishul Muslimeen claimed to be holding the hostages but some Afghan government officials said a criminal gang may have been responsible for the abductions.
Despite the hostages’ release, United Nations staff are likely to continue with strict security precautions, travelling with armed escorts and observing a strict curfew.