O'Brien stepped down in February as archbishop of Edinburgh and St. Andrews after three priests and a former priest charged he had been involved in sexual misconduct. He also agreed not to participate in the conclave that chose a successor to Pope Benedict XVI.
The Vatican statement didn't disclose O'Brien's destination but said he would leave Scotland for several months. Church officials said O'Brien's future remains in the hands of the Vatican.
"His eminence cardinal Keith Patrick O'Brien, archbishop emeritus of St. Andrews and Edinburgh, for the same reasons he decided not to participate in the last conclave, and in agreement with the Holy Father, will be leaving Scotland for several months for the purpose of spiritual renewal, prayer and penance," the statement said.