A group of survivors will watch the cardinal, who was too ill to return to Australia for questioning, give his videolink testimony to the commission in Sydney from a conference room at the Hotel Quirinale from 8am Monday (Australian time).
The cardinal arrived at the hotel via a side gate three hours early.
Reporters outside the hotel say Cardinal Pell's security team was heavy handed, pushing camera crews aside as he entered the hotel.
Cardinal Pell, who is now in charge of the Vatican's finances, will give evidence about the Catholic church's handling of abuse in the Ballarat diocese and Melbourne archdiocese.
The commission has heard about decades of widespread child sex abuse by a number of priests, including Australia's worst pedophile priest Gerald Francis Ridsdale, and Christian Brothers.
On the eve of his testimony it emerged he had tied a yellow ribbon at the Lourdes Grotto in the Vatican Gardens in support of Loud Fence, a movement supporting abuse victims that started in Ballarat and spread worldwide.
"This is my gesture of support, especially for the people of Ballarat," Cardinal Pell said in a statement.
"I hope the coming days will eventually lead to healing for everyone."
But Ballarat abuse survivors expect he'll still put the church before victims when he testifies to a royal commission.
A group of survivors and supporters have travelled to Rome to hear the senior Australian cleric's testimony at the elegant Quirinale Hotel from 8am on Monday (Australian time).
Andrew Collins, who was abused from the age of seven in Ballarat, said he would like to see the cardinal lay out what the church knew and when, and admit it did things wrong.
"Unfortunately, I think he will continue to say, `I don't recall, I don't remember' and to put the welfare of the church before the welfare of the people the church has hurt," he told AAP in Rome.
The 47-year-old said his survivor group was not on a witch hunt, but on quest for truth to ensure such abuse never happened again.
Cardinal Pell served in Ballarat between 1973 and 1984, presiding over a primary school where four Christian Brothers were pedophiles and living in a presbytery with Australia's worst pedophile priest, Gerald Ridsdale, in 1973.
