The sentence, the longest prison term possible for murder and terrorism under Norwegian law, includes the possibility of indefinite extension if a judge determines the self-proclaimed, far-right anti-Muslim extremist still is threat to society, the Financial Times reported.
Breivik, who confessed to bombing a government building in downtown Oslo, killing eight people, and then to going on a shooting spree on Utoya Island, killing 69 participants attending a Labor Party youth summer camp, July 22, 2011, smirked as the sentence was read.
His prison term was reduced by 445 days for the time he spent in jail since his capture.
The five-judge panel's unanimous verdict rejected the prosecutors' demand that Breivik be sentenced to psychiatric treatment.
"Norwegian society today takes an important step forward in the accounting for the gruesome events on 22 July last year," said Helga Pedersen, the Labor Party's deputy leader. "Today my thoughts go above all to all those who are missing someone they lost. But I hope that the verdict can help close a chapter."
Breivik said his massacre was justified in his campaign against multiculturalism in Norway and Europe and the "deconstruction of the Norwegian ethnic group."
The New York Times reported Breivik gave a right-wing salute as he entered the courtroom.
Many survivors of Breivik's massacre have said they want closure and hoped Friday's verdict would end their nightmare, the British newspaper The Independent said.
In a 10-week trial that ended in June, Breivik's attorneys argued their client was sane when he went on his rampage and should be sentenced to prison. Prosecutors countered that he was mentally ill and not criminally responsible, so hospitalization was a proper sentence.
The New York Times said it wasn't immediately clear whether the prosecution would appeal.
Judge Wenche Elizabeth Arntzen, reading from the 90-page decision, debunked Breivik's assertion that he was part of a network called the Knights Templar, saying the group's existence couldn't be proven.
Breivik had maintained he wanted to be found accountable for his actions and said he wouldn't appeal unless the court found him insane, the Financial Times said.
He had complained that to be declared mentally ill would be a "fate worse than death."
If declared sane, "Norway is going to be saddled with a martyr who will end up being idolized by right-wing fanatics across the world," Norwegian political analyst and commentator Anders Giaever told The Independent before the verdict was announced.
The killer previously announced plans to write and publish a book on his racist anti-Muslim philosophy.