Here is the Chihuahua Breed Standard: per American Kennel Club
Jana Runnels
Email:
tholexnic@verizon.net
* Chihuahuas are known by judges and handlers to be a "head breed" meaning that often times the body and movement
are overlooked for that big round skull and large eyes (expression) but, as you see in the written standard body and
movement are just as important and a good breeder should breed for both not just a typie head. Health should always
be kept in mind when creating new life. (Just my thoughts... ~Jana)
General Appearance
A graceful, alert, swift-moving little dog with saucy expression, compact, and with terrier-like qualities of temperament.

Size, Proportion, Substance Weight
A well balanced little dog not to exceed 6 pounds.

Proportion
The body is off-square;hence, slightly longer when measured from point of shoulder to point of buttocks, than height at the
withers. Somewhat shorter bodies are preferred in males.

Disqualification
Any dog over 6 pounds in weight.
Head
A well rounded "apple dome" skull, with or without molera.

Expression
Saucy.

Eyes
Full but not protruding, balanced, set well apart - luminous dark or luminous ruby. (Light eyes in blond or white-closed dogs
permissible.)

Ears
Large, erect type ears, held more upright when alert, but fairing to the sides  at a 45 degree angle when in repose, giving
breadth between the ears.

Muzzle
Moderately short, slightly pointed. Cheeks and Jaws lean.

Nose
Self-colored in blond types, or black. In moles,blues and chocolates, they are self colored. In blond types, pink nose
permissible.

Bite
Level or scissors. Overshot or undershot bite, or any distortion of the bite or jaw, should be penalized as a serious fault.

Disqualification
Broken down or cropped ears.
Neck, Topline, Body Neck
Slightly arched, gracefully sloping into lean shoulders.

Topline
Level

Body
Ribs rounded and well sprung (but not too much "barrel-shaped").

Tail
Moderately long, carried sickle either up or out, or in a  loop over the back, with tip just touching the back  (never tucked
between the legs.)

Disqualifications
Cropped tail; bobtail
Forequarters
Shoulders
Lean, sloping into a slightly broadening support above straight forelegs that set well under, giving free play at the elbows.
Solders should be well up, giving balance and soundness, sloping onto a level back. (Never down or low.) This gives a
chestiness, and strength of forequarters, yet not of the "bulldog" chest.

Feet
A small, dainty foot with toes split up but not spread, pads cushioned. (Neither the hare or the cat foot.)

Pasterns
Fine

Hindquarters
Muscular, with hocks well apart, neither out nor in, well let down, firm and sturdy. The feet are as in front.
Coat
Smooth coat
In the smooth coats, the coat should be of soft texture, close and glossy.(Heavier coats with undercoats permissible.) Coat
placed well under body with ruff on neck preferred, and more scanty on the head and ears. Hair on tail preferred furry.

Long coat
The coat should be of a soft texture, either flat or slightly curly, with undercoat preferred.

Ears
Fringed. (Heavily fringed ears may be tipped lightly if due to the fringes and not to weak ear leather, never down.)

Tail
Full and long (as a plume). Feathering on feet and legs, pants on hind legs, pants on the hind legs and large ruff on the
neck desired and preferred.

Disqualification
In long coats, too thin a coat that resembles bareness.
Color
Any color-solid, marked or splashed.
Gait
The Chihuahua should move swiftly with a firm, sturdy action, with good reach in front equal to the drive from the rear. From
the rear, the hocks remain parallel to each other,  and the foot fall of the rear legs follows directly behind that of the forelegs.
The legs, both front and rear, will tend to converge slightly toward a central line of gravity as speed increases. The side view
shows good, strong drive in the rear and plenty of reach in the front, with head carried high. The towline should remain firm
and the back line level as the dog moves.

Temperament
Alert, with terrier-like qualities.

Disqualifications
Any dog over 6 pounds in weight.
Broken down or cropped ears.
Cropped tail, bobtail.
In long coats, too thin a coat that resembles bareness.
For greater detail of the standard, see www.chihuahuaclubofamerica.org