Dan Jacobs, a Ford staffer, tweeted a picture of the former mayor giving two thumbs-up while dressed in a hospital gown.
"Ready to roll," Jacobs wrote alongside the picture.
Ford checked into the hospital around 6 a.m. ET, Jacobs said. In the hours leading up to his surgery, Ford read the day's news and spent time speaking with his wife, Renata.
Four surgeons will be involved in Ford's operation, which could take up to 10 hours.
The surgery is the latest cancer treatment for the former Toronto mayor and the one he has been hoping for. Ford had said if chemotherapy and radiation failed to shrink the tumours to an operable size, his chance at survival was low.
Months of recovery expected
Jacobs said doctors will make two main incisions, both about 30 centimetres in size, to remove a five-centimetre tumour from Ford's abdomen.
Following the surgery, Ford is expected to spend time in the post-operative recovery area before being transferred to the surgical stepdown unit.
Ford said he expected that he'll spend about four months recovering from the surgery.
Ford had been seeking re-election as mayor when he went to the hospital complaining of stomach pain. Doctors discovered the tumour, and he was soon diagnosed with liposarcoma.
He decided to drop out of the mayoral race and put his name on the ballot in Ward 2 instead.
On election day, Ford was then elected as the councillor in the ward he had long represented before he became mayor.
His brother, Doug Ford, took his place in the mayoral race, but ended up losing to John Tory.
At council last week, Tory said that Rob Ford is "a fighter," and that council is pulling for him as he heads into surgery.