More than 1,300 patients do not show up for hospital appointments every day, costing the Health Service more than €210,000 daily.
New figures published in the Irish Independent show that more than a fifth of return patients fail to keep follow-up appointments in some hospitals.
It also means that others on the waiting list are losing out.
Hospitals, which are losing millions a year because of missed appointments, are to crack down on the no-shows, taking patients off waiting lists if they do not have a valid excuse for failing to turn up.