The Vatican said the pope met the five victims, four women and a man, in London and was "moved by what they had to say and expressed his deep sorrow and shame over what victims and their families had suffered".
The pope ended the third day of his visit by conducting a giant open-air prayer vigil for 85,000 pilgrims in Hyde Park.
Thousands of protesters opposed to the pope's stance on clerical abuse, gay rights, contraception and a host of other issues marched through central London ahead of the vigil.
Organisers of the "Protest the Pope" march said more than 10,000 people had taken part. Demonstrators waved banners saying "Pope's opposition to condoms kills people" and "Pope -- male chauvinist pig".
After the meeting with the victims at the Vatican's embassy, a Vatican spokesman said the pope prayed with them "and assured them that the Catholic Church is continuing to implement effective measures designed to safeguard young people".
But abuse victims taking part in the protesters' march rejected the pope's expression of sorrow as "inadequate" and claimed the Vatican was continuing to cover up the abuse scandal which has rocked the Catholic Church.
Sue Cox, 63, who was sexually abused by a priest from the age of 10, said: "They need to open their secret files to the authorities, to independent scrutiny, and start making amends to all those people they've damaged."
The pope has previously met with victims while on visits to Malta, the United States and Australia.
Meanwhile, police continued to question six men detained by counter-terrorism officers on suspicion of plotting an attack linked to the visit.
The Vatican played down the arrests of the men, who work as street cleaners in central London, saying it had "never attributed much importance" to them.
Security remained tight on Saturday, with police closing key roads in the capital along the route the popemobile took to Hyde Park.
The head of the Roman Catholic Church started the day by meeting British Prime Minister David Cameron and expressed his condolences for the death of the premier's father last week.
After the mass at Westminster Cathedral he visited a residential home in Vauxhall, south London, where the 83-year-old pontiff said he himself had experienced the "joys and the struggles" of age.
Pilgrims had streamed into Hyde Park for hours before the prayer vigil began. Families shared picnics, waved flags and many of the faithful likened the atmosphere to a music festival.
In contrast to the hostility at the protesters' march, one banner said: "We're with you 100 percent Papa".
The pope will fly by helicopter to the city of Birmingham in central England on Sunday to conduct the beatification mass of Cardinal John Henry Newman, a 19th century convert from Anglicanism to Catholicism.
He will then return to Rome at the end of a visit which commentators say has helped to improve the strained relationship between the Roman Catholic church and Anglicans.
Benedict is only the second pope -- after John Paul II 28 years ago -- to visit predominantly Anglican Britain since king Henry VIII split with the Roman Catholic Church in 1534 over its refusal to annul his marriage.
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