Reprinted from the 2010 USEF Rule Book
1. Regardless of one’s equestrian skills and/or accomplishments, a person is an amateur for all competitions conducted under Federation rules who after his/her 18th birthday, as defined in GR101, has not engaged in any of the following activities which would make him/her a professional. Exception: In the Dressage Division, individuals are only eligible to compete as amateurs from the beginning of the calendar year in which they reach age 22. See DR119.3. In the Reining Division, amateur status will be determined per Reining Division Non Pro Conditions; see amateur status RN105. (For professionals wishing to be re-classified as amateurs, see GR1308.2a):
a. Accepts remuneration for riding, driving, showing, training, schooling or conducting clinics or seminars.
b. Accepts remuneration for giving riding or driving lessons, lessons in showmanship, instructions in equitation or horse training. (Persons acting as counselors at summer camps, who are not hired in the exclusive capacity of riding instructors are excluded and persons giving instruction and training to the handicapped).
c. Accepts remuneration for employment in other capacity (e.g., secretary, bookkeeper, veterinarian, groom, farrier) and gives instruction, rides, drives, shows, trains or schools horses, other than horses actually owned or leased by him/her, when his/her employer or a member of the family of said employer or a corporation which a member of his/her family controls, owns, boards or trains said horses.
d. Accepts remuneration for the use of his or her name, photograph or other form of personal association as a horseman in connection with any advertisement or article (including but not limited to clothing, product, equipment, etc.) to be sold.
e. Accepts prize money in equitation or showmanship classes. Prize money may be accepted by amateur riders in Dressage.
f. Rides, drives or shows, any horse for which he/she or a member of his/her family or a corporation which a member of his/her family controls, receives remuneration for boarding, training, riding, driving or showing. (A family member of a trainer may not absolve themselves of this rule by entering into a lease or any other agreement for a horse owned by a client of the trainer).
g. Gives instruction to any person or rides, drives or shows any horse, for which activity another person in his/her family or corporation which a member of his/her family controls will receive remuneration for the activity. (A family member of a trainer may not absolve themselves of this rule by entering into a lease or any other agreement for a horse owned by a client of the trainer).
h. Accepts remuneration, as defined in GR1306.2d, for selling horses/ponies, acts as a paid agent in the sale of horses/ponies or takes horses/ponies on consignment for the purpose of sale or training other than those owned wholly or in part by him/her or by a member of his/her family or farm/ranch/syndicate/partnership/corporation which he/she or a member of his/her family controls.
i. Advertising professional services such as training or giving lessons by way of business cards, print ads, or internet.
j. For Amateurs in Jumper Sections, see JP117.
k. For Amateurs in Eventing sections, see EV Appendix 3 - Participation in Horse Trials.
2. The following activities do not affect the amateur status of a person who is otherwise qualified:
a. The writing of books or articles pertaining to horses.
b. Accepting remuneration for officiating as a judge, steward, technical delegate, course designer, announcer or participating as a TV commentator, or accepting bona fide remuneration for services as a veterinarian, groom, farrier, tack shop operator or breeder, or for accepting bona fide remuneration for boarding services.
c. Accepting reimbursement for any expenses directly related to the horse (i.e. farrier/vet bills, entries) however, does not include travel, hotel, room and board or equipment.
d. Accepting a token of appreciation, other than money, for riding, driving or showing in halter/in hand. (Note: Horse board, prize money, partial support or objects of more than $300 are considered remuneration, not small tokens of appreciation). (Also note: accepting any amount of money, whether more or less than $300, is considered remuneration.) Prize money won by an amateur-owner rider/driver/handler in any class (other than equitation or showmanship) is not considered remuneration.
e. Having the occupation of veterinarian, groom, farrier or owning a tack shop or breeding or boarding stable in itself, does not affect the amateur status of a person who is otherwise qualified.
f. Any person who is serving an internship for college credit through his/her respective, accredited college program, and who has never held professional status, can accept reimbursement for expenses without profit.
Read more about the how the amateur rule works in the article "Confused About Amateur Rules ?"