Gilberte Bussiere, a 74-year-old originally from Asbestos, Que., was kidnapped on April 5 along with Gianantonio Allegri and Giampaolo Marta.
All three had been working as missionaries in the country.
Bussiere's cousin, Michel Belanger, who still lives in Asbestos, said the family felt relief after weeks of worry.
"We were almost expecting the worst," he told The Canadian Press. "But now, everything has changed, everything is fine. So we're very happy."
A member of Montreal's Congregation de Notre-Dame, Bussiere arrived in Cameroon in 1979 and lived there ever since, working as an educator.
She returned to Canada briefly last year for health reasons, but soon went back "to the country and the people she loved," according to the congregation.
Bussiere required medication and the family was concerned she would suffer without access to medical care, Belanger said.
Bussiere's congregation said she was reportedly in good health when she was freed. She was taken to Yaounde, Cameroon's capital, and placed in the care of the congregation.
"It is with great joy that the Sisters of the Congregation de Notre-Dame have learned (on Sunday) of the release of Sister Gilberte Bussiere and fathers Marta and Allegri," the congregation said in a statement on its website.
Foreign Affairs Minister John Baird said he was relieved Bussiere was released.
"Glad to have confirmation from #Cameroon govt that a Canadian citizen has been released by kidnappers. Hope she is healthy as well as safe," Baird tweeted Sunday.
The priests were assigned from the Vicenza diocese in northern Italy.
The Italian Foreign Ministry thanked Canadian and Cameroon authorities but gave no details of how the abduction ended.
The Italian Foreign Ministry cautions against travel in the area where they were abducted, 30 kilometres from the border with Nigeria "in consideration of the risk of kidnappings due to presence of jihadist elements coming from Nigeria."
At the time of the abductions, Vatican Radio said it wasn't ruled out that Boko Haram, an extremist Islamic group, might have been behind their kidnappings.
Vatican spokesman the Rev. Federico Lombardi said Pope Francis had followed the case from the beginning.
"We thank the Lord that this case reached a positive conclusion," Lombardi said, adding a thought for others who have been abducted in conflict zones.
"At the same time, we continue to pray and commit ourselves so that every form of violence, hate and conflict in various regions of Africa and in other parts of the world can be overcome."
Boko Haram's five-year-old Islamic uprising based in northeastern Nigeria has claimed the lives of thousands of Muslims and Christians, including more than 1,500 people killed in attacks so far this year. A French priest abducted in northern Cameroon late last year was released in January, though there was never any claim of responsibility.
- with files from Louis Cloutier and The Associated Press
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