The Maine Coon breed standard varies between the different cat-associations around the world. Here I have chosen the TICA breed standard for a Maine Coon cat. At the end of the page you can find links to other cat-associations.
  BODY: Torso: Large, long, rectangular, but not slender.
Legs: Medium to form a rectangle with the body with substantial boning and musculature.
Feet: Large, round and well-tufted.
Boning: Substantial.
Musculature: Substantial, powerful.
 

HEAD:
Shape: Broad, modified wedge,medium in size, with a gently curving forehead and high prominent cheekbones. A distinct stop can be felt under cheekbones.
Chin: Firm, in line with nose and upper lip.
Muzzle: Square.
Profile: Gentle concave slope. Allow for a slight bump at the end.
Neck: Medium-long, with sturdy musculature.
  Eyes: Large, slightly oval,appear round when wide open. Wide-set. Aperture is slightly oblique; toward outer base of ear. Color is any shade of green and/or gold, blue and odd-eyes accepted in whites. No relationship between coat and eye colors.
  Ears: Large, tall, wide at base. Set high on head with a very slight
outward tilt. Bases no more than an ear's width apart. Lower base set just slightly further back than upper base. Moderately pointed. Lynx tips extend vertically from the top back of the ear. Furnishings extend horizontally beyond outer edge of ear.
  Tail: Wide at base and tapering to tip with full, flowing hair at least as long as the body from shoulders tobase of tail.
  COAT/COLOR/PATTERN:
Length: Uneven; shorter on shoulders, gradually lengthening
down the back and sides. Frontal ruff, long; full shaggy britches and belly fur. A full ruff is not expected; however, there should be frontal ruff beginning at the base of the ears.
Texture: All-weather coat. Coat has distinct body, falling smoothly along body. A slight undercoat is carried. Not cottony or wooly.
Color: Traditional Category, all divisions, all colors. White trim
around eyes, lips, and chin allowed except in solid colors.
   
 

The Maine Coon´s colours and the official groups
   
  All colours are allowed except "masks". White arond chin and lips can be found on augoti cats.
 
  Maine Coon is divided into nine color-groups:
 

1. Black or blue
2. Black or blue with white
3. Brownagouti and blueagouti.
4. Brownagouti and blueagouti with white.
5. Red, creme, black-turtle, blue-turtle both agouti and nonagouti.
6. Red, creme, black-turtle, blue-turtle both agouti and nonagouti with white.
7. Silver
8. Silver with white
9. White
  CFA-standard
  MCBFAs standard
  TICA-standard
  Rasringen MaineCoon-katten (swedish page)