|Akaoua Babiana, the wife of Cameroon's deputy PM, was among the hostages released|
They include the wife of Cameroon's Vice-Prime Minister, Amadou Ali.
They were seized in two separate raids in May and July close to the Nigeria border. It is not clear how their release was secured.
Boko Haram is seeking to establish an Islamist state in Nigeria but its fighters often cross the long and porous border with Cameroon.
Many Nigerian civilians in border towns have fled to Cameroon to escape militant attacks, which have been stepped up in recent months.
In July, Cameroon, Nigeria, Chad and Niger agreed to form a 2,800-strong regional force to tackle Boko Haram militants. And that was the last I heard of that force. Why only 2800? I can see the other countries not putting more resources into this unit, but Nigeria has 500,000 military and paramilitary personnel. It looks like they probably dedicated about 1000 troops to this task force. I would have thought 10,000 would be more appropriate if you actually wanted to eliminate Boko Haram. It would appear that the government of Nigeria is not in any hurry to end the war.
Cameroon has reinforced its troops in its northern regions.
|Chinese hostages, who were released after being kidnapped in raids blamed|
on the Nigerian Islamist group Boko Haram, arrive in Yaounde on 11 Oct 2014
|The freed hostages were said to be relieved to be released but weak|
"But they are very weak. They are in very poor physical condition."
President Paul Biya announced their release said in a statement on state radio: "The 27 hostages kidnapped on May 16, 2014, at Waza and on July 27, 2014, at Kolofata were given this night to Cameroonian authorities."
|This map makes it obvious how vulnerable the northern part of Cameroon is to attack|
No details were given on the circumstances of the release or whether a ransom was paid.
In July, Cameroon said Mr Ali's wife, Akaoua Babiana, and her maid were abducted in "a savage attack" on his home in Kolofata by Boko Haram militants.
Mr Ali managed to escape to a neighbouring town.
Efforts to step up regional co-operation gained momentum after Boko Haram caused an international outcry by abducting more than 200 girls from a boarding school in north-eastern Nigeria.
The girls are thought to be held in the vast Sambisa forest, along Nigeria's border with Cameroon.