ATP International Series Gold (known from 1990 to 1999 as the ATP Championship Series) was a series of professional tennis tournaments held internationally between 2000 and 2008 that were part of the ATP Tour. The tournaments were positioned below the ATP Masters Series, and above the ATP International Series in terms of prize money and ranking points available.
International Series Gold tournaments offered players cash prizes (purses from $755,000 to $1,426,250 as of 2008) and the ability to earn ATP ranking points. See Association of Tennis Professionals#ATP rankings for more details.
Effective in 2009, this series of tournaments became the ATP Tour 500, incorporating many of the same tournaments. The "500" represents the number of ATP ranking points earned by the winner of each event in the series.