The health watchdog received more than 230 complaints about the care of people with disabilities last year.
They include allegations of abuse, neglect and assault.
The details have been released to Newstalk under the Freedom of Information Act.
Last year, the Health Information and Quality Authority (HIQA) received 236 complaints about residential centres for adults and children with a disability.
According to one complaint, a resident was removed from a centre by their guardian because they were neglected, with dirty clothes, nails and hair.
There are several complaints of financial abuse – one involving large amounts of money unaccounted for.
There are also reports of service-users absconding from centres, with one walking along a road at night.
Meanwhile, there is a separate report of a resident having unexplained bruising.
Others include allegations of emotional and psychological abuse, medication errors and staff shortages.
There is also a report of a service-user being regularly assaulted and bullied by another patient.
Dr Sarah Donnelly, from the school of social work in UCD, said the complaints are very concerning.
“I think it clearly speaks to the need for additional protections and oversight in disability centres and private nursing homes,” she said.
“There is clearly a lack of oversight.”
HIQA said it does not have a remit to investigate individual complaints, but all unsolicited information is used to inform the authority's monitoring of each residential centre.
The HSE declined to comment on the individual issues, but said it does have a comprehensive complaints procedure in place.