United Kennel Club:

General Appearance
The Sarplaninac is a medium-sized dog who looks bigger than he is because of heavy bone and thick coat. Any solid color is acceptable but the most common is an iron gray. The length of body is slightly longer than its height at the withers, and the head is in proportion to the size of the body. Ears are drop and V-shaped and the tail is long and carried like a saber. The Sarplaninac should be evaluated as a working livestock guardian capable of protecting stock in mountainous terrain, and exaggerations or faults should be penalized in proportion to how much they interfere with the dog's ability to work.
The head length of a dog of average height is about 9¾ inches from occiput to tip of nose, but this length will vary in proportion to the size of the dog. In profile, the muzzle is slightly shorter in length, measured from stop to nose, than the skull, measured from stop to occiput. The stop is slight.
The skull is slightly domed and broad between the ears, tapering gradually toward the muzzle. The median furrow is distinct. The supraorbital ridges are only slightly developed and the occiput is not evident. Cheek muscles are well developed but the cheekbones are flat.
MUZZLE -- The muzzle is broad and deep at the base, tapering slightly toward the nose. The top line of the muzzle is straight except for the tip, which is unusually developed giving an aquiline appearance in profile. Lips are moderately thick, tight, and dry. The upper lip only slightly overhangs the lower lip.
Faults: Insufficiently broad skull; muzzle too long.
Serious fault: Muzzle too snipey.
Disqualification: Total lack of pigment in lips.
TEETH -- The Sarplaninac has a complete set of evenly spaced, white teeth meeting in a scissors bite.
Serious fault: Level bite.
Disqualification: Undershot or overshot bite; missing teeth.
The nose is broad and black, projecting somewhat over the mouth and giving the impression that the upper jaw is longer than the lower. Viewed in profile, a line drawn from the tip of the nose to the chin slants downward and backward.
Disqualification: Total lack of pigment in nose.
Eyes are almond-shaped and of moderate size. Eye color ranges from dark brown to chestnut. The expression is piercing. Eye rims are black.
Disqualification: Total lack of pigment in eye rims.
The ears are drop and V-shaped, hanging close to the cheeks, and covered with short, dense hair. When pulled forward, the tip of the ear should reach the inner corner of the eye. The ears are set on, or just below, a line running from the tip of the nose through the inner corner of the eye.
Serious faults: Ears set too high; ears not hanging close to cheeks.
The neck is of medium length but appears shorter than it is because of the thickness of the coat. The neck is broad and well muscled, and blends smoothly into the head and shoulders. The skin is tight with no dewlap. The crest of the neck is straight or slightly arched. The head is carried slightly above the line of the back.
The shoulder blades are long and wide and lay back at an angle of about 65 degrees from the horizontal. The upper arm is muscular and lies at an angle of about 55 degrees from the horizontal. The elbows are close to the body. The forelegs are straight, strong, and sturdy in bone, with strong, broad, slightly sloping pasterns. The length of the foreleg is slightly greater than one-half the distance from the withers to the elbow.
A properly proportioned male Sarplaninac is 8 to 10 percent longer (measured from prosternum to point of buttocks) than tall (measured from the withers to the ground), with a little more length of body allowed in bitches (10 to 12 percent longer). The withers are moderately developed and broad. Whether the dog is standing or moving, the line of the back is strong and level from the withers to the slightly sloping croup. A very slightly sloping top line is acceptable but not preferred. The loin is moderately short, muscular, and deep, with very little tuck-up. The ribs extend well back and are well sprung out from the spine, forming a broad, strong back, then curving down and inward to form a deep body. The brisket extends to the elbow. Viewed from the front, the chest between the forelegs is broad and muscular.
The hindquarters are muscular, wide, and set somewhat wider apart than the forelegs. The rear angulation is slightly more open than the angulation of the forequarters, with the angle of the stifle about 125 degrees and the angle of the hock about 130 degrees. When the dog is standing, the broad rear pasterns are perpendicular to the ground and, viewed from the rear, parallel to one another.
The feet are firm and oval-shaped, with well-arched and closed toes. The nails are strong and dark in color. The pads are tough, elastic, and darkly pigmented. Front dewclaws may be removed; rear dewclaws should be removed.
The tail is a natural extension of the top line. It is thick and muscular at the base and tapers to the tip in a saber shape. A tail of the correct length extends at least to the hock. When the dog is relaxed, the tail hangs down naturally. When the dog is moving or alert, the tail is raised level with, or slightly above, the back. When very agitated, the tail may be raised over the back.
Disqualification: Bobtail (including dogs born with a stump tail or no tail).
Coat and Skin
The Sarplaninac is a double-coated breed with a long, straight, somewhat rough-textured outer coat, and a shorter, much finer and thicker undercoat. The coat on the head, ears, and front side of the legs is short. The hair on the neck, the buttocks, the tail, and the back side of the legs is longer. This variation in coat length results in a ruff at the neck, a distinct frill at the nape of the neck, breeches on the buttocks and backs of the legs, and a plume on the tail. At the withers, the outer coat should be 4 to 5 inches long and no shorter than 2¾ inches. Skin is moderately thick, elastic and tight all over the body.
Minor faults: Coat slightly shorter than desired, as long as the feathering is correct.
Disqualification: Coat on the withers shorter than 2¾ inches.
All solid colors are acceptable from white to a very dark brown that is nearly black. The most common color is an iron gray. The color may vary from a darker shade on the top of the head, neck, and body, to a lighter shade toward the extremities, but the change must be very gradual so as not to give the impression of spots or patches of color. The hairs of the outer coat may be tipped in black resulting in a sable color pattern. Tiny white markings on the chest and toes are allowed but not desirable.
Minor fault: White markings on the chest and feet.
Disqualification: White spots or patches other than tiny white markings on chest or toes; brindle; albinism.

Here is a link to a blog I wrote, with photos of the various Colors of the Sarplaninac

Height and Weight
Height at maturity, measured at the withers is 24 inches or over for males and 22½ inches or over for females.
Mature males in good working condition weigh between 77 and 99 pounds. Mature females in good working condition weigh between 66 and 88 pounds.
Disqualification: Mature male under 22 inches; mature female under 21 inches.
At the trot, the Sarplaninac moves freely with strides of moderate length. The back and loin are elastic and springy. As speed increases, however, the width between the legs decreases and the tendency to single track increases until the dog breaks into a heavy, lumbering gallop. When alert, the Sarplaninac moves with determination and purpose toward the object of interest, often with the head slightly lowered and the tail raised above the back.
Unilateral or bilateral cryptorchid. Extreme viciousness or shyness. Total lack of pigment in lips, nose, or eye rims. Undershot or overshot bite. Missing teeth. Bobtail (including dogs born with only a stump or no tail at all). Coat on the withers shorter than 2¾ inches. White spots or patches other than tiny white markings on chest or toes. Brindle. Albinism. Mature male under 22 inches; mature female under 21 inches.