The Mastiff Club Of America requires its members to adhere to the following guidelines which constitute its Code Of Ethics. The Club also requires that members, breeders, and stud dog owners not aid or abet the violation of these guidelines by anyone else. This Code of Ethics details certain practices necessary to implement the Objectives of the Club as outlined in Article 1, Section 2, of its Constitution.

1. I will consider only the betterment of the breed when breeding a bitch or allowing a breeding with my stud dog, being conscious of controlling and eliminating inherited problems. A breeder and stud dog owner shall plan each breeding with the paramount intention of protecting the breed; and only when the parties involved agree the breeder is in a position and has the knowledge to give proper care to both bitch and offspring.

2. I will not allow a bitch to be bred prior to her reaching twenty-two (22) months of age, nor shall any bitch be bred after her seventh (7) birthday. A bitch will not be bred more than once (1) a year unless she does not whelp a litter, the litter is stillborn, consists of a single (1) pup, or as part of a veterinarian's recommendation for treatment of pyometra. Any other reason for a bitch to be bred more than once a year would need to be stated in writing, along with a licensed veterinarian's certification of good health, to be received by the Recording Secretary at least (45) forty-five days prior to the breeding for the Board's approval.

3. I will sell a Mastiff only to a buyer whom I believe to be interested in the protection of the breed and who would agree in writing to provide the highest quality of care for said Mastiff, including food, water, proper shelter from heat or cold, active companionship, appropriate exercise, socialization, and professional veterinary care whenever necessary.

4. An MCOA member will sell each Mastiff puppy/adult on a written contract signed by all parties. Said contract shall contain, but is not limited to, the following provisions:
a) Complete care/feeding instructions.
b) A record of inoculations and worming with a recommended continuation schedule.
c) Provide the buyer with a (3) generation pedigree on this litter.
d) Furnish a signed AKC registration or transfer form, unless written agreement is made with the buyer that such papers are withheld or are to follow.
e) A provision that ensures that the breeder is contacted whenever an owner can no longer keep a dog at anytime in the dog's life.
f) Stipulate that the buyer have a veterinary check-up within (5) working days of the sale, (or whatever is applicable in your state of residence), to determine that the Mastiff is healthy. If the veterinary determines that the Mastiff is not in good health, the breeder will, upon the Mastiff's return, refund the purchase price or replace the Mastiff.

5. I will not knowingly sell or provide a Mastiff for resale, gift, or prize, or to a broker/agent for resale. I will not engage in the brokering of puppies, (selling or buying), except in a case that would prevent a potential rescue situation. ALL SUCH CASES MUST be documented by letter to the MCOA Recording Secretary.

6. I will not sell a puppy/adult who is sick, nor will I ship or deliver to the buyer a puppy less than eight (8) weeks of age.

7. I will show good sportsmanship at all times and in all matters relating to Mastiffs. I will maintain the highest degree of honesty and integrity. I will not knowingly make a misstatement of fact in any serious discussion or advertisement of my Mastiffs, or the Mastiffs of any other Mastiff owner, that I might have with persons not qualified to judge for themselves.

8. If I should find myself unable to physically take back a Mastiff , bred/sold by me, who has been displaced, I will assist MCOA Rescue or a regional club rescue program in the placement of said Mastiff.

9. I will require the neutering/spaying of any puppy/adult I place or sell as pet quality as soon as the dog reaches the appropriate age.

10.I will not sell a Mastiff for the purpose of attack training, fighting, or any other sport detrimental to the breed and its reputation.

11.I will not produce more than eight (8) litters, owned or co-owned, in a twenty-four (24) month period. As a stud dog owner, I will not knowingly allow my stud dog to be used in a program which has already produced more than eight (8) litters in a twenty-four(24) month period.