The Chihuahua is a tiny dog with an apple-shaped head and a short pointed muzzle. It has round, very dark eyes, sometimes dark ruby or luminous in color. The large ears, which are seen as a trademark, should be held erect. Chihuahua puppies have a soft spot or "molera" on the top of the skull. The bone usually closes the gap by adulthood. The body is cobby, and the tail is curled over the back or to the side.

There are two types of Chihuahuas: the most common short-haired variety, and the long- haired type. Colors include fawn, sand, chestnut, silver and steel blue, but any color is accepted, including black & tan and parti-color. The dog is heartier than he looks. Chihuahuas have a level back, and legs that come down straight and square.

These dogs are extremely small - the smallest breed in the world. The breed standard says they shouldn't weigh more than 6 pounds, and in the British breed standard it even states that if two dogs are relatively equal in a show, the smaller one should be given preference. In the pet world, as opposed to the show world, Chihuahuas often grow as big as 12 pounds. They stand just 6 - 9 inches tall. Most other dogs would probably consider them abite sized treat.

"Teacup" Chihuahua is a misleading term as there is only one breed standard. Some people may describe a Chihuahua as teacup, pocket-sized, tiny toy, miniature, or standard, attempting to convey that a particular dog is worth a higher price or better in some way. The Chihuahua Club of America points out that there is only one breed standard, and any individual dog may weigh anywhere from 2 to 12 pounds. Adding a modifier in front of the breed name is not correct, as there is no such thing as a miniature or teacup Chihuahua, and smaller dogs of the breed are not any different or more valuable than the larger examples except in the mind of some buyers.

The Chihuahua comes in two coat types: short hair and long. Paradoxically, the long-haired type actually sheds less than the short-haired type. The short haired dog is sometimes called smooth-coated, although this, too, is misleading, as the fur may have a whiskery feel to it. The long coated type generally looks fluffy due to a downy undercoat which also makes them feel very soft. Short haired Chihuahuas require very little care. Long haired Chihuahuas need a bit more grooming, but still do not need to be brushed more than once a week.