UPDATE (10.58am):
Police have located an elderly man after he went missing overnight in the Blue Mountains.
Patrick Flanagan, 88, was found safe and well in Katoomba on Tuesday morning.
Mr Flanagan had been reported missing by medical staff at Katoomba Hospital on Woodlands Road on Monday night.
He was located at a nearby residence about 9am on May 22.
Earlier:
A search for an elderly man is underway in the Blue Mountains, after he went missing overnight.
Patrick Flanagan, 88, was last seen by medical staff about 8pm on Monday, May 21 at Katoomba Hospital on Woodlands Road, however he was noticed missing about 10pm.
Staff contacted police and a search of the immediate area commenced.
A wider search will continue this morning including officers from the Blue Mountains Police Area Command, Rescue and Bomb Disposal Unit, Polair and Dog Unit.
Mr Flanagan is described as being of Caucasian appearance, 175m tall with a thin build.
He was last seen wearing a dark-coloured fleece jumper and trousers. Mr Flanagan walks with a cane and has difficulty walking long distances.
Anyone who has information or sights Mr Flanagan is urged to contact Crime Stoppers on 1800 333 000.