Historically the Cocker Spaniel in the United States has reached the top of breed popularity in the A.K.C. a number of different times. It is small so it is a great size for a household companion and has a perpetual puppy look about the face. It has a merry and happy personality and seems to be the perfect companion for children. In part due to this popularity, the dog has been so widely bred that it has lost much of its original hunting instinct and is seldom used in these days as a hunting dog. Dogs historically who have enjoyed this extent of popularity often lose not only the instinctive qualities for which they were bred, but also the temperament can become unstable. The American Cocker Spaniel, previously considered by many to be a darling dog with sweet disposition, developed some unreliable temperament over the years and presently has been noted as one of the smaller dogs which is unreliable in temperament and can frequently be a "biter". Unfortunately not enough notice is taken of this since it is a smaller dog, however, in lists of dogs that bite in studies taken across the U.S., the Cocker is high on the list.

The English Cocker Spaniel is a close cousin. Both dogs derive their name from the practice of using these breeds to hunt the woodcock. Their smaller size and agile bodies could penetrate the thickets and brush which is the woodcocks' habitat. The English Cocker has retained more of the hunting instinct and is still used as a gun dog.

In the conformation show ring of the United States, due to the huge popularity of the Black Cocker, the Cocker Club applied to the American Kennel club to show this dog in a separate group, so as to allow for the other varieties, the Parti-Color and the ASCOB (any solid color other than black), to have their chance. Thus the American Cocker Spaniel is one of the very few breeds which is shown in separate classes even though are actually one breed. As a result, in the Sporting Group, there will be three representatives of the Cocker Spaniel being shown.

The coat of the Cocker Spaniel is luxuriant and flowing. It has been somewhat over emphasized when breeding for show, and can be quite unmanageable for the folks who have this dog as a family pet. Usually a pet Cocker is kept trimmed . If care is not taken to maintain the coat either through brushing or trimming it can become a serious problem, full of mats and tangles .Buyers who purchase puppies need to understand the necessity for coat care in this breed.

The breed is also susceptible to a number of disease conditions, including skin problems and allergies, eye problems, epilepsy and ear infections. Many of these problems stem from the over breeding of the dog in commercial breeding kennels, where little emphasis is ever placed on health and temperament, and now it will take a number of years to eliminate such problems from the genetic pool. Breeders who are concerned about this have made a strong effort recently to breed not only those dogs who have been tested for health problems but also those dogs who have a stable temperament.