George Dodds, 72, was reported missing at 6.50pm on Thursday after leaving his home in Woodlands View, Cleadon, at around 1pm.
Officers are handing out leaflets and searching the South Tyneside area for him.
Northumbria Police operational manager Mick Hall said: “We really want to bring George home safely and would ask the people of Cleadon and the South Tyneside area to be vigilant and check their gardens and sheds.
"We are very grateful to the public for their help so far and would ask them to continue to support us in the search for George.”
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Officers have released a picture of George in the hope that someone may have seen him since his disappearance and have since received reported sightings of him.
George, who has problems with his memory and may become lost and confused, is described as white, of thin build, with short white hair.
He is believed to be wearing a dark puffer jacket, blue trousers, dark shoes and a black beanie hat.
Anyone who may be able to assist police in locating him is asked to call 101 quoting log 901 25/04/19.