The Bullmastiff is an English breed of dog of mastiff type and large size, with a solid build and a short muzzle. It was developed as a guard dog in the nineteenth century by cross-breeding the English Mastiff with the now-extinct Old English Bulldog. It was recognised as a breed by The Kennel Club in 1924.

Bullmastiff Dog
Height Males
64–69 cm (25–27 in)[1]
61–66 cm (24–26 in)[1]
Weight Males
50–59 kg (110–130 lb)[1]
41–50 kg (90–110 lb)[1]
Coat Short and weather resistant
  • Any shade of brindle
  • red
  • fawn
Life span 10.2 years
Kennel club standards
The Kennel Club standard
Fédération Cynologique Internationale standard
Dog (domestic dog)



The origins of the Bullmastiff are unclear. In the 18th century, in some regions of England, the English Mastiff and Old English Bulldog were commonly inter-bred to produce dogs suitable for guarding people and their property. By the beginning of the 20th century, this cross-breed was in widespread use as an aid to gamekeepers in the control of poaching.[2] They were bred for strength, size and speed using a cross of the tough, heavy and aggressive 19th century Bulldog with the large, strong, less aggressive Mastiff.[3] As a result, the Bullmastiff is known as the Gamekeeper's Night Dog.

The Bullmastiff was recognised as a breed by The Kennel Club in 1924. Dogs had to have a minimum of four generations of descent from Bullmastiff stock without input from either Bulldog or Mastiff; cross-bred animals could not be registered.[2] The American Kennel Club recognised it in 1934.[4]
It was definitively accepted by the Fédération Cynologique Internationale in 1955.[5]

In 1928, the De Beers diamond mining company imported Bullmastiffs to South Africa to guard the mines.[6]


A male, fawn Bullmastiff
Young Bullmastiff male standing in the snow
Brindle Bullmastiff

The Bullmastiff is a large dog. Bitches stand some 61–66 cm at the withers, and usually weigh 41–50 kg; on average, dogs stand about 3 cm taller and weigh 9 kg more.[1]

The coat may be fawn, red or brindle, in any shade; some limited white marking on the chest is allowed. The muzzle is black, becoming paler towards the eyes.[1]

The Bullmastiff is brachycephalic, flat-faced and short-muzzled, but this does not affect its breathing.[7][failed verification]



A 2024 UK study found a life expectancy of 10.2 years for the breed compared to an average of 12.7 for purebreeds and 12 for crossbreeds.[8]

Health concerns within the breed include hip and elbow dysplasia, progressive retinal atrophy, bloat, and cancer, with a relatively high incidence of lymphoma and mast cell tumours.[9][10][11] Bullmastiffs are prone to certain hereditary diseases, including:

An autosomal dominant form of progressive retinal atrophy is common in the breed. A mutation to the RHO gene is responsible.[15]

See also



  1. ^ a b c d e f FCI-Standard N° 157: Bullmastiff. Fédération Cynologique Internationale. Accessed February 2022.
  2. ^ a b Eric Makins ([1938]). The Bullmastiff. Manchester: 'Our Dogs' Publishing Co.
  3. ^ Walkey B. The Bullmastiff Fancier's Manual. Sechelt B.C., Canada: Coast Arts Publishing; 1992
  4. ^ Get to Know the Bullmastiff. The American Kennel Club. Retrieved 29 May 2014.
  5. ^ FCI breeds nomenclature: Bullmastiff (157). Fédération Cynologique Internationale. Accessed February 2022.
  6. ^ "Breed standard (Appendix A)" (PDF). Archived from the original (PDF) on 16 August 2012. Retrieved 18 September 2012.
  7. ^ Brachycephalic dogs. The Kennel Club.
  8. ^ McMillan, Kirsten M.; Bielby, Jon; Williams, Carys L.; Upjohn, Melissa M.; Casey, Rachel A.; Christley, Robert M. (1 February 2024). "Longevity of companion dog breeds: those at risk from early death". Scientific Reports. 14 (1). Springer Science and Business Media LLC. doi:10.1038/s41598-023-50458-w. ISSN 2045-2322. PMC 10834484.
  9. ^ Bell J, Cavanagh K, Tilley L, Smith FWK. Veterinary Medical Guide to Dog and Cat Breeds. Hoboken: Teton NewMedia; 2012.
  10. ^ Edwards DS, Henley WE, Harding EF, Dobson JM, Wood JLN (2003). "Breed incidence of lymphoma in a UK population of insured dogs". Veterinary and Comparative Oncology. 1 (4): 200–6. doi:10.1111/j.1476-5810.2003.00025.x. PMID 19379181.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. ^ Dobson JM (2013). "Breed-predisposition to cancer in pedigree dogs". ISRN Veterinary Science. 2013: 1–23. doi:10.1155/2013/941275. PMC 3658424. PMID 23738139.
  12. ^ Orthopedic Foundation for Animals. "Hip Dysplasia Statistics". Archived from the original on 19 October 2010. Retrieved 11 June 2013.
  13. ^ Orthopedic Foundation for Animals. "Elbow Dysplasia Statistics". Archived from the original on 3 September 2011. Retrieved 11 June 2013.
  14. ^ Orthopedic Foundation for Animals. "Thyroid Statistics". Archived from the original on 30 May 2013. Retrieved 11 June 2013.
  15. ^ Oliver, James A.C.; Mellersh, Cathryn S. (2020). "Genetics". In Cooper, Barbara; Mullineaux, Elizabeth; Turner, Lynn (eds.). BSAVA Textbook of Veterinary Nursing (Sixth ed.). British Small Animal Veterinary Association. p. 131. ISBN 978-1-910-44339-2.