The ATP Tour is the elite tour for professional men's tennis organized by the Association of Tennis Professionals (ATP). The ATP Tour includes the four Grand Slam tournaments, the ATP World Tour Finals, the ATP Super 9, the Championship Series and the World Series tournaments.

This is the complete schedule of events on the 1998 ATP Tour, with player progression documented from the quarter-final stage.
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These are the rankings of the top twenty players of the ATP Tour, at the end of the 1997 ATP Tour, and of the 1998 season, with number of rankings points, highest and lowest position during the year, and number of spots gained or lost from 1997 to 1998.

These tables present the number of singles (S), doubles (D), and mixed doubles (X) titles won by each player and each nation during the season, within all the tournament categories of the 1998 ATP Tour: the Grand Slam tournaments, the ATP Tour World Championships, the ATP Super 9, the ATP Championship Series, and the ATP World Series.

^ Rios also won the Grand Slam Cup, which on December 9, 1999, merged with the ATP Tour World Championship, the ATP's year-end tournament also held annually in Germany. This gave birth to the present ATP World Tour Finals.

Titles won by nation (singles):

The following players won their first career title: