Pet Advisor Blog

USA Tosa Dog – Dog Breed Guide

Breed summary

Size: Giant
Weight: 83 to 200 pounds
Height: around 24 inches
Longevity: 12
Bark Tendency: Low
Aggression: Low
Compatibility to other pets: High


The USA Tosa dog breed is one of two Tosa fighting dog breeds that are being bred today. USA Tosa dogs are heavier and bigger when compared to the traditional Japanese Tosa variety. In the USA, these dogs are grouped according to weight classes:

  • Lightweight Tosa Class
  • Middleweight Tosa Class
  • Heavyweight Tosa Class.

In addition, these dogs are affectionate with heir family but can be quite aloof with strangers.

Official Name

USA Tosa
This is the popular name for the Tosa Inu in the United States


Date – Post World War II
Country – Native to Japan and bred as a separate breed in the United States
Family / Group – Mastiff, Guardians

Recognized By:

Continental Kennel Club
Fédération Cynologique Internationale
National Kennel Club
American Pet Registry, Inc.
American Canine Registry
Dog Registry of America, Inc.
North American Purebred Registry, Inc.
American Kennel Club – Foundation Stock Service Program


USA Tosa dogs were bred directly from the Japanese Tosa dogs that were used as ceremonial fighting dogs and were famously called as the Sumo Wrestlers of the canine blood sports. The USA Tosa is the younger Tosa variety, with its breeding and development initiated after World War II. This is the time where Tosa-Inu dogs in Japan nearly went extinct. American GI stationed in the land of the rising sun decided to revitalized the fighting breed and brought several specimens in the United States.

From there, the USA Tosa grew to massive proportions and recognized in the West as a separate and distinct dog breed from their original Tosa-Ken progenitors.


The USA Tosa is the Western version of the Japanese fighting dog. This American varieties are bigger and heavier but share the same traits and characteristics of their Asian progenitors. The USA Tosa dogs are powerful and decisive. When at home USA Tosa dogs are affectionate and devoted to their handlers and families. However, they can be very aggressive when around strangers. Therefore, early age socialization is very important.

Bred For

The USA Tosa was brought to the US to save a nearly extinct dog breed. They grew bigger and heavier than the original Japanese breed, but the two varieties were bred to be fighting dogs as well as guardians.


The USA Tosa may not be the ideal apartment dog due to its massive size and tendency to give out dig and deep barks. An ideal living environment for these dogs is a rural or suburban house with a big yard where they can run freely.


The USA Tosa dog is wearing a short coat that is very easy to groom and maintain. These are mastiff dogs so drooling should be expected. They are dogs that shed hair lightly. Therefore, brushing them once or twice a week should be enough to maintain their coat healthy.


USA Tosa dogs are the Western counterpart and larger versions of the original Japanese Tosa fighting dogs. They share the same traits and temperament and are easy to train as long as handlers use dominant, calm and persistent training methods.

As for any dog, early age socialization and training will help your puppy to grow up in a friendly and happy grown-up dog.


Eye problems, hip and elbow dysplasia and bloat are the most common health problems that plague the USA Tosa dog.


The USA Tosa needs to go on a daily walk or jog. Also, these dogs need to be trained to maintain their muscular stance and physical prowess. To sum up, everyday walks and running sessions will help maintain your dog’s health.