Legitimate American & International Dog Registries

AKC - American Kennel Club - (the AKC Rules on registering foreign bred dogs has a good list of International Dog Registries http://www.akc.org/rules/special-registry-services/)

UKC - United Kennel Club- (the United Kennel Club was founded in 1898 & is not to be confused with the Universal Kennel Club listed below).
KC - Kennel Club   (AKC equivalent in The United Kingdom)
CKC - Canadian Kennel Club (AKC equivalent in Canada)
FCI - Federation Cynologique Internationale (AKC equivalent in most other foreign countries)
Other Registries That May Be Valid & Working Towards a Quality Breed or Trait

Rare or New Breed Registries
The Registries* below should NOT be confused with the Parent Breed Club or National Club of already recognized & registered purebred registries of the AKC, UKC, CKC or FCI

AADR - All American Dog Registry
ABCA - American Border Collie Association
ACDCA - American Cattle Dog Club of America
ADBA - American Dog Breeders Association
AIBC - American International Border Collie Association
APBR - American Pit Bull Registry (can be questionable)
ARBA - American Rare Breed Association
ARHA - American Rabbit Hound Association
ASCA - Australian Shepherd Club of America
ISDS - International Sheep Dog Society
JRTCA - Jack Russell Terrier Club of America
NASDS - North American Sheep Dog Society

* Some Rare Breeds or New Breeds have Independent Registries BEFORE they apply to become a register-able with organizations such as the AKC. These registries are not recognized broadly & may not mean anything to a reputable breeder because the dogs cannot be shown to the broader audiences of the AKC, UKC, CKC or FCI countries.

Working Dog Registries

Although I have not listed any, there are registries that are for WORKING dogs who compete in field trials. This is particularly true for hunting dogs who may actually be of mixed breed, but are very carefully documented, often with decades of generations of proven field dogs. Be aware that if you are buying a dog for work, referrals are one of the most crucial tools to use.

Fake/Bogus Registries - this list is not comprehensive. Dog Registries come & go or change names as they get bad press.

AAPBA - All American Premier Breeds Assoc. (All American Pit Bull)
ACA - American Canine Association
ANDR - American National Dog Registry
APRI - American Pet Registry, Inc (also, American Purebred Registry; no "I")
APBR - American Pit Bull Registry
ARU - Animal Registry Unlimited
CKC - Continental Kennel Club (do not confuse w/ Canadian Kennel Club)
CRCS - Canine Regisration and Certification Services
DRA - Dog Registry of America
FIC - Federation of International Canines
NAMBR - North American Mixed Breed Registry
NAPDR. - North American Purebred Dog Registry
NKC - National Kennel Club
UABR - United All Breed Registry
UKC - Universal Kennel Club (do not confuse this with the legitimate United Kennel Club)
UKCI - Universal Kennel Club International
WKC - World Kennel Club
WWKC - World Wide Kennel Club
Questionable registries:
BFK/BFKC - Bonafide Kennel Club
IABCA - International All Breed Canine Association of America
SDR - Sporting Dog Registry