The win ended a 17-game Oakland losing streak against teams in the AFC West.
The Raiders (3-8) have won two straight games after losing the previous six. The Chiefs (4-7) have dropped four in a row.
Lamont Jordan ran for a touchdown for Oakland and Daunte Culpepper completed 15 of his 22 passes for 170 yards.
Kansas City's Kolby Smith, in his first NFL start, carried 31 times for 150 yards and two touchdowns.
Brodie Croyle was 12-of-23 for 145 yards with an interception.