AKC Chihuahua Standard, Revised 1972
Head: A well-rounded “apple-dome” skull, with or without molera. Cheeks and jaws lean. Nose moderately short, slightly pointed (self-colored, in blond types, or black). In moles, blues and chocolates, they are self colored. In blonde types, pink nose is permissible.
Ears: Large, held erect when alert, but flaring at the sides at about an angle of 45 degrees when in repose. This gives breadth between the ears. In long coats, ears fringed. (Heavily fringed ears may be tipped slightly, never down.)
Eyes: Full, but not protruding, balances, set well apart–dark ruby or luminous. (Light eyes in blond types permissible.)
Teeth: Level or Scissors bite. Overshot or undershot bite or any distortion of the bite should be penalized as a serious fault.
Neck and Shoulders: slightly arched, gracefully slopping into lean shoulders, may be smooth and the very short types, or with a rough about the neck preferred. In long Coates, large ruff about neck desired and preferred. Shoulders lean, slopping into a slightly broadening support above straight four legs that are set well under, giving a free play at the elbows. Shoulders should be well up, giving balance and soundness, slopping into a level back. (never down or low.) This gives a chestiness, and a strength of four quarters, yet not of the “bulldog chest”; plenty of brisket.
Back and body: level back, slightly longer than in height. Shorter back desired in males. Ribs rounded (but not too much “barrel shaped”.)
Hindquarters: muscular, with hocks well apart, neither out nor in, well let down, with firm sturdy action.
Tail: moderately long, carried sickle either up or out, or in a loop over the back, with tip just touching the back. Never tucked under. Hair on tail in harmony with the coat of the body, preferred furry in smooth coats. In long coats full and long as in a plume.
Feet: small, with toes split up but not spread, pads cushioned, with fine pasterns. (Neither the hare nor the cat foot) A dainty, small foot with nails moderately long.
Coat: In the smooth, the coat should be soft texture, close and glossy. Heavy coats with under coats permissible. Coat placed well over body with ruff on neck, and more scanty on head the ears. In long coats coat should be of a soft texture, either flat or slightly curly with under coat preferred. Ears fringed (heavily fringed ears may be tipped slightly, never down), feathering on feet and legs, and pants on hind legs. Large ruff on the neck desired and preferred. Tail full and long as a plume.
Color: any color solid, marked or splashed.
Weight: a well balanced little dog not to exceed six pounds.
General appearance: a graceful, alert, swift moving little dog with saucy expression. Compact, with terrier-like qualities.
Disqualifications: cropped tail, bobtail. Broken down or cropped years. Any dog over 6 pounds in weight. And in Long Coats, too thin coat that resembles baldness.
Copyright American Kennel Club.