The Yorkshire Terrier called Daisy, belonging to William Lee, was found around some lakes by a member of public, in North Warwickshire on Sunday.
William was last seen with Daisy near Sutton Coldfield on Friday.
A member of public reported seeing them on Old Kingsbury Road in Minworth at around 7pm that day.
William's car was discovered five miles away along Slade Lane in Dosthill, Tamworth, on Saturday morning.
Staffordshire Police, which is helping with the search, says Daisy had been found around Kingsbury and Middleton Lakes.
Police are now carrying out an in-depth search of the area, including the shores of both lakes.
Daisy is in good health and being cared for by family members.
Detective Chief Inspector Ash Farrington, from Staffordshire Police, said: "We are still putting all our efforts into finding William safe and well and so we are utilising specialist search dogs to help us target that search.
"We continue to support the family during this stressful time and I ask for anyone that may know anything about William’s movements in the past 48 hours to come forward and potentially help our efforts."
William, who is a keen walker, has been missing since he left his home on Friday at 3.30pm.
He is described as white, of slim build, standing at 5ft 6in tall, with white hair. He was wearing a light-coloured jacket, beige jumper and trousers.
Specialist search officers, with the support of the national police air service, have been taking part in the search.
Anyone with information is asked to contact Staffordshire Police, quoting incident number 755 of 16 April.