The annual report from the Mental Health Commission has listed the Adult Mental Health Unit at Roscommon hospital as being "unfit for purpose".
The work of the commission is to foster and promote high standards of care and good practice in the mental health services, and to ensure the interests of people who are involuntarily committed are protected.
While the Roscommon unit scored an 87% compliance rating during a recent inspection, today's report says the maintenance of premises at acute centres varies greatly around the country.
It lists the centre at Roscommon as being one of a number of older units which are not fit for purpose due to lack of physical space.
The centre has a maximum capacity of 24 residents, including 22 beds in the main unit, and an additional two beds at the high-dependency facility.
The report also shows the unit in Roscommon reported three instances of overcapacity in the last year.
