McCain's narrow victory over Obama breaks a bellwether streak in which Missourians had picked the winning presidential candidate in every election since 1956.
With all jurisdictions reporting complete but unofficial results, McCain led Obama by 3,632 votes Wednesday out of more than 2.9 million cast -- a margin of 0.12 percentage points.
Both men spent considerable resources trying to win Missouri, a state that Obama ultimately did not need for his national victory.
Obama won 365 electoral votes. Missouri's 11 electoral votes will give McCain 173.