Northern Ireland's Historical Abuse Inquiry has been told that 20% of the 1,000 boys who were residents of De La Salle home in Co Down allege that they were physically or sexually abused.
The home opened in 1950 and closed in 1985 and its residents were mainly boys, aged between 11 and 16 from north or west Belfast.
The information about the percentage of allegations was given this morning by Joseph Aiken, junior counsel to the inquiry, in his opening remarks at the module dealing with the De La Salle home, Rubane House, in Kircubbin, Co Down.
Mr Aiken said allegations of physical or sexual abuse, or both, have been made against all five of the brothers who were in charge of the home up to 1980, but that the De La Salle Order is not in a position to accept the allegations against all of the said individuals.
He also referred to allegations against one Brother, now deceased, of sexual and physical abuse over a 20-year period.
Mr Aiken said the inquiry will hear accounts of abuse carried out by Father Brendan Smyth at Rubane House and at another home run by the Nazareth Order in Belfast.
To date, the inquiry has heard evidence about two homes run by the Nazareth Sisters in Co Derry and a child migration scheme that sent residents of Northern Ireland institutions to care homes in Australia.
The inquiry was set up by Northern Ireland's power-sharing administration at Stormont.
It is chaired by former High Court judge Anthony Hart.
Its remit is to investigate what took place at 13 residential children's homes run by religious orders, voluntary organisations and the state in the 73-year period up to 1995.
Recently, Banbridge Courthouse heard evidence about a child migrant scheme, which shipped residents of Northern Ireland care homes to institutions in Australia.
The system was operated by the UK and Australian governments.
Before that the inquiry heard the evidence of former residents, staff and nuns from two residential homes operated by the Nazareth Order in Derry.