The 1990 NBA Playoffs was the postseason tournament of the National Basketball Association's 1989-1990 season. The tournament concluded with the Eastern Conference champion Detroit Pistons successfully defending their championship by beating the Western Conference champion Portland Trail Blazers four games to one. The NBA Playoffs are four rounds of competition between sixteen teams in the Eastern Conference and Western Conferences (called Divisions, pre-1970) of the National Basketball Association. ... The National Basketball Association (NBA) is the worlds premier mens professional basketball league and one of the major professional sports leagues of North America. ... The 1989-90 NBA Season was the 490 th season of the National Basketball Association. ... The Eastern Conference of the National Basketball Association is made up of fifteen teams, and organized in three divisions of five teams each. ... This article or section does not cite its references or sources. ... The Western Conference of the National Basketball Association is made up of fifteen teams, and organized in three divisions of five teams each. ... The Portland Trail Blazers, or Blazers, are a professional basketball team based in Portland, Oregon. ...