There were 44 assaults in Castlerea Prison last year.
New figures show a total of 320 assaults in Irish prisons in 2020.
250 involved prisoners attacking other inmates - with 64 in Cork jail, 44 in Castlerea in Roscommon, and 29 in Midlands Prison in Portlaoise.
There were also 70 assaults by prisoners on staff.
Jim Mitchell, from the Prison Officers Association, says several staff have suffered serious injuries over the years....