Pope Francis was doing well after surgery for an inflamed large colon, but the 84-year-old was expected to spend around seven days recovering in hospital, the Vatican said.
The pontiff was admitted to Rome's Gemelli hospital yesterday for a scheduled operation under general anaesthetic for symptomatic diverticular stenosis of the colon.
Francis "is in good general condition, alert and breathing spontaneously", spokesman Matteo Bruni said in a statement, adding that the surgery "lasted about three hours".
"A stay of about seven days is expected, barring complications," he said.
A week earlier, on the eve of the feast of Saints Peter and Paul, Francis seemed to hint at the upcoming operation, saying: "I ask you to pray for the pope, pray in a special way. The pope needs your prayers."
The pontiff had already put his Wednesday general audience on hold for the summer, and has no other official appointments in his calendar until next Sunday, when he is due to lead the Angelus prayer.
Italy's Prime Minister Mario Draghi sent Francis "affectionate get well soon wishes".
Sheikh Ahmed el Tayyeb, the Grand Imam of Al-Azhar, one of the Muslim world's leading authorities, wished the pontiff "a speedy recovery".
Francis is in the same suite on the 10th floor of the Gemelli hospital used by Pope John Paul II.
The late pope underwent surgery there seven times, including after an attempt on his life in 1981, and for a tumour in the colon in 1992.
The suite has a bed, television and ensuite bathroom, as well as a little sitting-room with a sofa bed and a small altar, according to the ANSA news agency.
The corridor housing the suite is guarded by Italian and Vatican police, it said.
Pope Francis is sometimes short of breath because a part of one of his lungs was removed following an illness when he was a young man in his native Argentina.
He also suffers from sciatica, which causes pain that radiates from the lower back along the sciatic nerve to the legs.