In a nonpartisan blanket primary, incumbent Democrat J. Bennett Johnston won reelection to a fourth term, avoiding a runoff on November 6, 1990, by receiving 54% of the vote.

Former Ku Klux Klan leader David Duke placed second, as the leading Republican challenger.

With Bagert failing to gain traction, the National Republican Senatorial Committee tried to recruit former Governor David Treen to enter the race.

[4] Bagert's name remained on the ballot, but under state law his votes could not be counted as part of the official tally.

"[6] Republicans Johnston would retire at the end of this term, succeeded by fellow Democrat Mary Landrieu.