Stanley Victor Howard was last seen on Sunday (June 21) at 6.45pm at his home address in Greenford Road, Greenford.
He said he was going to the shops and did not return.
He is described as a white man, around 5ft 4ins tall, of medium build with grey balding hair.
Stanley suffers from dementia and has limited use of one side of his body.
He was last seen wearing a three-quarter-length black/grey coat, black boots and a blue cardigan.
Anyone with information on his whereabouts should contact Ealing CID on 101 or Missing People on 116 000 quoting reference 15MIS023835.