1999 ATP Tour World Championships

The ATP 1999 World Cup was a tournament in the men's professional tennis, which was played on indoor carpet courts. It was the 30th edition of the competition in singles and 26th in doubles, both were part of the ATP Tour in 1999. The individual competition was held 2000 Tennis Dome at the Exhibition Grounds in Hanover in the last week of November in the EXPO, the double competition took place a week earlier in the Hartford Civic Center in Hartford, Connecticut in the United States instead. It was the last staging of the event, in the following year became the ATP World Championships - together with the competing Grand Slam Cup - detached from the Tennis Masters Cup.

Defender of the single was Àlex Corretja, who this time did not quite qualify. The final was Pete Sampras won against Andre Agassi and won for the fifth and last time the ATP World Cup - so he was next to Ivan Lendl record title holder; only in 2011 Roger Federer could break that record when he won the year-end event for the sixth time. In double Jacco Eltingh and Paul Haarhuis were defending champions, but only Haarhuis entered 1999 with another partner. Sébastien Lareau and winners were Alex O'Brien, the first and only time ATP World Champions were performed with a final victory over Mahesh Bhupathi and Leander Paes.