To find out whether a dog is registered with the American Kennel Club, enter its registered name and breed into the AKC's free dog lookup tool on its website. This tool also lets you search by registration number if you want to confirm that registration.
If you are buying an AKC-registered dog, it should come with documentation. Breeders need to register the litter with the AKC for the puppies to be eligible for individual registration, and they need to provide registration applications to buyers. Adult dogs should come with their registration papers, which you can transfer into your name by having both the buyer and seller sign the back and mailing them to the AKC. Some dogs may be eligible for limited registration without paperwork, but they must meet certain requirements.
If the registration papers are lost, the person who the AKC has listed as the current owner can request a duplicate copy. The organization does not release registration papers to anyone else. If the breeder or previous owner refuses to give you the papers, you can file a complaint with the AKC.
Beware of breeders or sellers who claim to have lost the papers or who tell you that you can register the dog without any documentation from them. A trustworthy seller should give you the paperwork at the time of sale.