An annual ceremony will take place in Croke Park to commemorate those who went out and never came home.
Burning candle on black table. Memory dayThere are nearly 900 long-term missing persons registered on the island of Ireland with Gardaí appealing for anyone who has any information on a missing case to come forward as a matter of urgency.
Minister of State at the Department of Justice James Browne has previously encouraged families of missing persons who have not yet provided a DNA sample to consider doing so.
Meanwhile Trevor Deely's family say they have not given up hope that their loved one may walk through the front door of the family home once again.
The Kildare man was last seen heading home from a work Christmas party on the 8th of December 2000 and will be gone 23 years on Friday.
He's one of those who will be remembered today at the ceremony to mark Missing Persons Day.
