Eight players, who are generally on the All-Star Game rosters (though this is not necessitated by rule), are selected for the Home Run Derby and compete in a traditional playoff system where the players with the most home runs advance to the next round. Each player gets ten "outs" per round, where an out is defined as any swing that is not a home run in this case. Should a tie exist between players at the end of any round, the number of regular-season home runs by the All-Star break is the first tiebreaker and the distance of the longest home run in the first round is the second tiebreaker. Until 2006, the home run count was reset after each round. However, a rule change was made for the 2006 Home Run Derby which causes the home run count for the four players advancing to the second round to carry over. The home run count for the final round is still reset to zero.
Prior to 1991, the Home Run Derby was structured as a two-inning event with each player receiving five outs per inning which allowed for the possibility of ties.
Until 2004, the Home Run Derby consisted of four American League players and four National League players. However, in 2005, Major League Baseball chose to change the look of the contest, still having eight players, but with the players representing their home countries rather than their respective leagues. This was commonly looked upon as a lead-in to the World Baseball Classic which was played in March, 2006. Bobby Abreu, representing Venezuela, won the first International Derby with a record 41 home runs, including a record 24 in the first round. In 2006, the selection of four players from each league to participate in the Derby was resumed.
During the 2005 through 2007 derbies, the Golden Ball was used once a player reaches nine outs. If a batter hits a home run using the golden ball, Century 21 and Major League Baseball would team up to give $21,000 per home run to charity. In both 2005 and 2006, $294,000 was raised for charity, equaling 14 golden ball home runs per year. State Farm will continue this in 2007 as they will designate $17,000 (one dollar for each of State Farm's agencies), a reduction of $4,000, to a charity unknown as of now in 2007, with Major League Baseball's donation being given to the Boys and Girls Clubs of America.
It is a popular notion that the Home-Run Derby can hinder the performance of a player for the rest of the year. Bobby Abreu, the 2005 champion, has had trouble refining his swing after entering the Derby. On the other hand, 2006 champion Ryan Howard seemed to improve his swing after the Derby, hitting for a much better average and slugging percentage over the second half.
The derby was first nationally televised by ESPN in 1993 on a same-day delayed basis. The first live telecast came in 1998. The event begins at 8 p.m. Eastern time. Although two hours were devoted to the telecast, it almost always ran over schedule. The 2006 derby, for example, lasted nearly three hours.