Huge crowds gathered to watch Pope Francis preside over Palm Sunday services in St. Peter's Square at the Vatican.
The service comes just a day after the 86-year-old pontiff was released from a three-day stay at Rome's Gemelli Hospital, where he received antibiotics intravenously to treat bronchitis.
On Saturday, before being driven away, he made a witty remark to journalists waiting for him at the hospital that he was "still alive."
Pope Francis leaves hospital; 'Still alive,' he quips
In a sign of his improved health, the Vatican released details of Pope Francis' Holy Week schedule.
An estimated 60,000 people attended the Mass, according to Vatican officials, and Francis greeted everyone in attendance, acknowledging that people had come from both nearby and faraway places to be there.
"I greet all of you, people from Rome and pilgrims, especially those who have come from far away. I thank you for your participation and also for your prayers, which intensified during these past days," said Francis, and he wished everyone a "good journey toward Easter!"
The holy day marks the start of celebrations during Holy Week in the Christian calendar leading up to Easter next week.
Pope Francis plans to preside over Easter services next week as well.