The Breeders' Cup Classic is a Grade I Weight for Age thoroughbred horse race for 3-year-olds and older run at a distance of 1+1⁄4 miles (2,000 m) on dirt. It is held annually at a different racetrack in the United States as part of the Breeders' Cup World Championships in late October or early November. All of the races to date have been held in the United States except for the 1996 edition held at Woodbine Racetrack in Toronto, Canada.

The Classic is considered by many to be the premier thoroughbred horse race of the year in the U.S., although the Kentucky Derby is more widely known among casual racing fans. Once the richest race in the world, in more recent years, only the Saudi Cup, Dubai World Cup, The Everest and Prix de l'Arc de Triomphe have had consistently higher purses. Often, the winner of the Classic goes on to win U.S. Horse of the Year honors, including the four winners of the race between 2004 and 2007—respectively Ghostzapper, Saint Liam, Invasor, and Curlin. Due to the extremely high quality of horses in the event, the race is notoriously hard to predict. One notable example of an underdog winning the Classic is the victory of Arcangues in 1993. This was the biggest upset in Breeders' Cup history and his $269.20 payoff for a $2 wager remains a Breeders' Cup record.

The Classic is now regarded as the fourth leg of horse racing's Grand Slam of Thoroughbred racing — the traditional Triple Crown (Kentucky Derby, Preakness Stakes, and Belmont Stakes) plus the Breeders' Cup Classic. After American Pharoah's Triple Crown win earlier in 2015, the term became popular; the colt became the first horse to ever accomplish this feat.

The first running of the Breeders' Cup Classic in 1984 produced an exciting finish between 30–1 longshot Wild Again on the inside, Gate Dancer on the outside and favorite Slew o' Gold in between. The three battled down the stretch with Wild Again shifting his path away from the rail and Gate Dancer "lugging in" towards the rail, squeezing out Slew O' Gold. Wild Again finished a neck in front of Gate Dancer with Slew o' Gold less than a length behind. After a 10-minute stewards' inquiry, Wild Again was left in first place but Gate Dancer was disqualified to third.

The 1987 renewal featured the face-off between two Kentucky Derby winners, Ferdinand and Alysheba. Ferdinand, who won the Derby in 1986, reached the lead in mid-stretch, then struggled to hold off the late charge of Alysheba. In a photo finish, Ferdinand prevailed by a nose and would later be named Horse of the Year. Alysheba came back in 1988 to win the Classic, becoming the then-leading money earner in history.

In the 1989 renewal, Sunday Silence and Easy Goer faced off for the last time in one of racing's most famous rivalries. Sunday Silence had beaten Easy Goer in the Kentucky Derby and Preakness Stakes but Easy Goer turned the tables in the Belmont. Easy Goer then won the Whitney, Travers, Woodward and Jockey Club Gold Cup, making him the 1–2 favorite in the Classic. Sunday Silence raced five lengths behind the early leaders, with Easy Goer six lengths further behind. Easy Goer made a move down the backstretch and got next to Sunday Silence, who then made his own move as they rounded the final turn. Sunday Silence opened up a three-length lead, but Easy Goer again started closing down the stretch. At the wire, Sunday Silence prevailed by a neck, earning him Horse of the Year honors.

The 1993 renewal saw the biggest upset in Breeders' Cup history when the French-based Arcangues won at odds of 133–1. California-based horses had dominated at Santa Anita in the preceding races, and Bertrando was expected to continue the trend. He set the early pace and had a comfortable lead coming down the stretch, only to be caught near the wire. Arcangues' jockey Jerry Bailey had timed the run perfectly, even though he had never ridden the horse before. "I couldn't understand the instructions the trainer (André Fabre) gave me in the paddock", he said. "I don't even know how to pronounce the horse's name. But sometimes a horse runs best when he is ridden by someone who has never been on him before."

In 1995, Cigar came into the Classic having won seven straight Grade I races and was made the 3–5 favorite. On a muddy track, he scored a 2+1⁄2 length victory in the excellent time of 1:592⁄5, then the fastest Classic ever run. When calling the race, track announcer Tom Durkin referred to him as the "unconquerable, invincible, unbeatable" Cigar – a phrase that would be associated with the horse for the rest of his life.