Completed in 1973 for United Racecourses, the stand was based on pioneering mixed-use American models.
The pre-cast concrete grandstand became one of the first in the UK to house a range of functions such as conference, exhibition and dining facilities.
Built in less than a year, the then-innovative, column-free cantilevered roof structure still allows spectators to have a clear view over the entire Surrey racecourse. At the rear of the grandstand is a south-facing parade ring.
The judges were particularly impressed by how well the structure, which appears 'almost new' in places, has aged.
They said: 'There are different elements of interest in the grandstand; the long, cable-supported cantilever roof beams, the precast double tees and the elements of precast cladding.
'The obvious feature of the grandstand is the cantilever beams supporting intermediate glazing panels that provide protection from the weather but leave a completely uninterrupted viewing facility.'
They added: 'The publicly visible sides and underneath of the beams have weathered well, with little visible dirt accumulation and staining.'
The accolade was presented to representatives from AukettFitzroyRobinson at the Concrete Society's annual dinner on Thursday.