He was flown by helicopter from the Castel Gandolfo papal summer residence to live permanently in Vatican City.
Greeted by Pope Francis as he arrived, he was driven the short distance to his new accommodation.
Benedict, 86, was last seen in public on 23 March and there has been speculation about his health.
Observers said at the time he appeared more frail than when he stepped down on 28 February.
However, Vatican spokesman Federico Lombardi said this week that Emeritus Pope Benedict was not ill.
Hours after his arrival, the Vatican issued a photograph of Benedict shaking hands with Pope Francis. However, unlike his departure from the Vatican, there was no live TV coverage of his return.