Maricopa County Judge Sherry Stephens could have sentenced Arias to life with the possibility of early release after 25 years, but decided the convicted killer should spend the rest of her life behind bars.
Before her sentence was handed down, Arias expressed remorse for her actions.
"To this day I can't believe that I was capable of doing something that terrible," Arias said. "I'm truly disgusted and repulsed with myself. I'm horrified because of what I did, and I wish there was some way I could take it back."
Earlier, Travis Alexander's sisters gave their victim impact statements. Hillary Alexander said she's trying to block her brother from her life.
"I don't want to remember him anymore, because it hurts too much to remember him alive. ... I remember how he was brutally taken from us and I can't handle it. This is what I've had to do so I can cope," she said through tears.
Arias, 34, was found guilty of first-degree murder in May 2013. The jury that convicted her found the murder was especially cruel, making Arias eligible for the death penalty. However, that same jury was unable to reach a unanimous decision on whether she should live or die.
A new jury was empanelled in October 2014 to decide Arias' fate, but they, too, were unable to reach a unanimous decision.
Because a second jury was deadlocked in the penalty phase of Arias' case, the death penalty was taken off the table, leaving Arias' sentence up to the judge.
Arias will serve her sentence at the Lumley Unit in the Arizona State Prison Complex-Perryville near Goodyear, Arizona.