Fifty-eight-year-old Richard Lane suspected the wallet was stolen at a leisure centre in his hometown of St Ives, Cambridgeshire in 1978.
The wallet contained his driving licence, gym membership card, union membership card and payment plan for a new TV, 'The Mirror' reported.
Richard, then a 23 year-old printer, also thinks he had around 15 pounds in cash inside it.
The wallet was found by the contractors behind a wall on the top floor, near the lift shaft.
However, the battered old wallet complete with everything apart from the money has now been found inside a brick wall cavity by builders refurbishing the leisure centre in St Ives.
An appeal to find the owner was launched and Richard, who lives about 160 km away in Evesham, Worcestershire, was alerted by his mother.