Pope Francis will have surgery on his abdomen on Wednesday afternoon at Rome's Gemelli hospital.
He is expected to stay in hospital for "several days" to recover from the hernia operation, the Vatican said.
The hernia is "causing recurrent, painful and worsening" symptoms, added Vatican spokesman Matteo Bruni.
The 86-year-old has faced a series of health issues in recent years, and uses a cane and a wheelchair due to a persistent knee ailment.
In a statement, the Vatican said the pontiff's medical team had decided in recent days that surgery was needed.
"In the early afternoon he will undergo a laparotomy and abdominal wall surgery... under general anaesthesia," said Mr Bruni.
He added: "The stay at the health facility will last several days to allow the normal post-operative course and full functional recovery."
Earlier on Wednesday, Pope Francis carried out his weekly audience as normal and didn't mention his planned operation.
The day before, the Pope was at the same Rome hospital for a scheduled check-up, months after he was taken to hospital with bronchitis.
He spent three days in hospital in March to treat a lung infection, in the same month that he marked the 10th anniversary of his pontificate.
In 2021, Pope Francis spent 10 days in hospital after having a part of his colon removed, in a bid to address a painful bowel condition. He recently revealed that the complaint had returned.
Last month, he pulled out of his Friday audiences due to a fever.
But while his predecessor Benedict XVI quit in 2013, the Pope has dismissed the possibility of leaving office too.
"You don't run the Church with a knee but with a head," he is said to have told an aide last year.
The Pope is considered to have been in general good health during his decade leading the Catholic Church
He continues to maintain a busy schedule, and is due to visit Portugal and Mongolia from August.