George Bass was last seen by his wife when he left his Harrogate home at around 11.15am on Wednesday, March 2.
She raised the alarm later that day when he didn't return home, which is out of character for George.
Police are urging Harrogate residents to check their garages, sheds and any outbuildings in case George has sought shelter.
The force has joined George's family in appealing directly to him.
They said: "If George sees or hears this appeal, please get in touch with your family or the police and let us know that you are safe."
It is believed that George has his bus pass with him and could have travelled away from the Harrogate area. He often travels to Leeds using the bus.
The last confirmed sighting of George was on King's Road, Harrogate near Sainsbury's at around 11.34am on the day he went missing.He is described as white, 5ft 4in tall with grey receding hair, brown eyes and a pale complexion.
He was last seen wearing a grey waterproof jacket with a blue fleece underneath, brown trousers, a dark blue hat, dark blue gloves and black shoes.Police are appealing to anyone, including public transport users, who have seen George since Wednesday morning or knows of his current whereabouts, to contact them.
Call North Yorkshire Police on 101, select option 1 and pass information to the Force Control Room.
The missing people charity are also supporting our appeal and can be contacted in confidence on 116 000.