Gardaí have appealed for assistance tracing 48-year-old Dublin man David O'Reilly.
He has been missing from his home in Rathmines since Tuesday, 19 February.
Mr O'Reilly was last seen in the city centre at about 8.30am.
He is 1.73m (5'8") tall, of stocky build, and has brown/grey hair and brown eyes.
Anyone with information on his whereabouts is asked to contact Rathmines Garda Station on 01-6666700, or the Garda Confidential Line 1800-666-111.