Mastiff Breed Standard

The name Mastiff derives from the Anglo-Saxon word "masty" meaning stout or powerful. It was first recorded in a Court role in 1251. Although the dogs of today are not perhaps exactly in the same form as they were then, the breed still retains the courage and guarding instincts so prized in his ancestors.

Kennel Club's Breed Standard Updated October 2009

With the kind permission of the Kennel Club,

we are able to present the current Breed Standard.

 Mastiff Breed Standard 

A Breed Standard is the guideline which describes the ideal characteristics, temperament and appearance of a breed and ensures that the breed is fit for function. Absolute soundness is essential. Breeders and judges should at all times be careful to avoid obvious conditions or exaggerations which would be detrimental in any way to the health, welfare or soundness of this breed. From time to time certain conditions or exaggerations may be considered to have the potential to affect dogs in some breeds adversely, and judges and breeders are requested to refer to the Kennel Club website for details of any such current issues. If a feature or quality is desirable it should only be present in the right measure.

General Appearance
Head, in general outline, giving a square appearance when viewed from any point. Breadth desired and in ratio to length of whole head and face as 2 : 3. Body broad, deep, long, powerfully built, on legs wide apart and set. Muscles sharply defined. Size is desirable, but only if combined with quality and if absolute soundness is maintained. Height and substance important if both points are proportionately combined.

Large, powerful, well knit frame. A combination of grandeur and courage.

Calm, affectionate to owners, but capable of guarding.  Usually indifferent with strangers; timidity is unacceptable.

Head and Skull
Skull broad between ears, forehead flat, but wrinkled when attention is excited. Brows (superciliary ridges) slightly raised. Muscles of temples and cheeks (temporal and masseter) well developed. Arch across skull of a flattened curve, with depression up centre of forehead from median line between eyes, to halfway up sagittal suture. Muzzle short, broad under eyes, and keeping nearly parallel in width to end of nose; truncated, i.e. blunt and cut off squarely, thus forming a right angle with upper line of face, of great depth from point of nose to under-jaw. Under-jaw broad to end. Nose broad, with widely spreading nostrils when viewed from front, flat (not pointed or turned up) in profile. Lips diverging at obtuse angles with septum, and slightly pendulous so as to show a square profile. Length of muzzle to whole head and face as 1 : 3. Circumference of muzzle (measured mid-way between eyes and nose) to that of head (measured before the ears) as 3 : 5.  Whilst in repose, any exaggeration of wrinkle or excess of loose skin is unacceptable in mature adults.

Moderate size, wide apart. Stop between eyes well marked but not too abrupt. Colour hazel brown, darker the better, showing no haw.  Loose eyelids highly undesirable.  Free from obvious eye problems.  

Small, thin to touch, wide apart, set on at highest points of sides of skull, so as to continue outline across summit, and lying flat and close to cheeks when in repose.

Canine teeth healthy; powerful and wide apart; incisors level, or lower projecting beyond upper but never so much as to become visible when mouth is closed.

Slightly arched, moderately long, very muscular, and measuring in circumference about 2.5-5 cms (1-2 ins) less than skull before ears.  

Shoulder and arm slightly sloping, heavy and muscular. Legs straight, strong and set wide apart; bones being large. Elbows square. Pasterns upright. Balanced and in harmony with hindquarters.

Chest wide, deep and well let down between forelegs. Ribs arched and well rounded. False ribs deep and well set back to hips. Back and loins wide and muscular; flat and very wide in bitch, slightly arched in dog. Great depth of flanks.  Topline level and maintained whilst on the move.  Length of body taken from point of shoulder to point of buttock greater than height at withers.  

Broad, wide and muscular, with well developed second thighs, hocks bent, wide apart, and quite squarely set when standing or walking.  Strength in hindquarters is of paramount importance, cow hocks in mature adults unacceptable.

Large, round and tight. Toes well arched. Nails black.

Set on high, and reaching to hocks, or a little below them, wide at its root and tapering to end, hanging straight in repose, but forming a curve with end pointing upwards, but not over back, when dog is excited.

Powerful, easy extension, driven from the rear, fluent, sound, with ground-covering strides.  Tendency to pace is undesirable.  Absolute soundness essential.

Short and close-lying, but coarser over neck and shoulders.

Apricot, fawn or brindle. In any case, muzzle, ears and nose should be black with black around eye rims, and extending upwards between them. Excessive white on body, chest or feet is unacceptable.

Any departure from the foregoing points should be considered a fault and the seriousness with which the fault should be regarded should be in exact proportion to its degree and its effect upon the health and welfare of the dog.

Male animals should have two apparently normal testicles fully descended into the scrotum.

Reproduced by Kind of Permission of The Kennel Club

Last Updated - October 2009 

1859 Standard first published by Stonehenge
1883 Standard drawn up by O.E.M.C
1890 A numerical value was given to the points of the mastiff which were printed with the standard until after the Second World War, when the system was abolished for all breeds.
1949 All Standards taken over by The Kennel Club rearranged, and a gait/movement clause was added.
1995 A slight clarification was made.

Standard first published by Stonehenge Standard drawn up by O.E.M.C  A numerical value was given to the points of the mastiff which were printed with the standard until after the Second World War, when the system was abolished for all breeds. All Standards taken over by The Kennel Club rearranged, and a gait/movement clause was added. A slight clarification was made.

The late Mrs Pam Day said in her forward to the 1980 Handbook

" Our great breed was saved from extinction immediately after the war when only seven dogs were traced. With imports from the USA and later South America (all of course going back to English exports) we have built today, forty years on a considerable number of pedigree dogs. Unfortunately, there are several types which must be most confusing to new breeders and onlookers. This means the breed standard in our new hand¬book is the most important item, if we keep the standard ever in our minds when we come to mate our dogs and bitches, we as perfectionists will think what mating will correct or enhance. "

It is now well over twenty years since Mrs Day wrote these words but her statements are as true today as they were then. When considering a mating the breed standard should always be in our minds. Some parts of the standard such as size, are open to interpretation, others such as head measurements are quite explicit.

We hope this breed standard will help you come to terms with what a mastiff should be.

Note: A number of mastiffs where also imported from Canada after the war, they made a great difference to the revival of the breed.