Almost every sport organization, amateur or professional, either conducts its own drug testing or participates in a drug testing program run by a larger organization. The National Collegiate Athletics Association (NCAA,) National Basketball Association, Women's National Basketball Association, National Football League, Major League Baseball, and National Hockey League each conduct their own drug testing programs. Each of these leagues has its own rules for testing and its own list of prohibited substances. The lists, however, are usually quite similar.
An Olympic-level athlete may be tested for drugs by a number of different sporting organizations, depending on the level at which he or she is competing at a given time. For example, someone who is selected for the U.S. Olympic team could be tested by International Olympic Committee (IOC), the United States Olympic Committee (USOC), and other national and international organizations that govern his or her sport.
Olympic athletes may be required to take "in-competition" and/or "out-of-competition" drug tests. In-competition drug testing at a specific competition. During the competition, the selected athletes are notified that they will be tested at the end of the event. The athletes who are selected (sometimes randomly, sometimes by place-finish in the event) must provide a urine sample while at the competition site. Out-of-competition drug testing occurs with no advance notice to the athlete. The athlete may be contacted at any time and at any place -- home, work, or training facility. Again, some organizations select athletes for out-of-competition drug tests randomly, and some select them by current ranking in the sport.