Spaying or neutering can be done as early as a few months old, dog owners should consult with their veterinarian to determine the best age to spay or neuter their pet. Many vets in the U.S. recommend spaying or neutering be done between 5 and 9 months of age. AKC's Canine Health Foundation conducted research that indicates there may be long-term health benefits to spaying or neutering dogs after they have passed through puberty.