The 1990 World Series matched the defending champions and heavily-favored Oakland Athletics against the Cincinnati Reds, with the Reds sweeping the Series in four games. It was the most recent National League sweep of the American League. It is remembered for Billy Hatcher's seven consecutive hits. This also was the second World Series meeting between the two clubs (Oakland won four games to three in 1972).
Athletics manager Tony La Russa and Reds manager Lou Piniella were old friends and teammates from their Tampa American Legion Post 248 team.
The Cincinnati Reds won the National League West division by five games over the Los Angeles Dodgers and set an NL record by staying in first place in the division for the entire season or "wire-to-wire", which had been done only one other time (1984 Detroit Tigers) and then defeated the Pittsburgh Pirates, four games to two, in the National League Championship Series.
The Oakland Athletics won the American League West division by nine games over the Chicago White Sox then defeated the Boston Red Sox, four games to none, in the American League Championship Series.
The Oakland Athletics were the defending World Series champions, two-time defending American League champions, and favorites against the Reds. The Oakland Athletics became the first franchise to appear in three consecutive World Series since the 1976–1978 New York Yankees. Their lineup consisted of three former AL Rookies-of-the-Year: José Canseco, (1986); Mark McGwire, (1987); and Walt Weiss, (1988). A's outfielder Willie McGee won a batting title that year, but it wasn't the AL batting title. He batted .335 for the NL's St Louis Cardinals before he was traded in late August to Oakland.
Behind starter Dave Stewart and reliever Dennis Eckersley, the Athletics had won 306 games over the prior three seasons