Special Circuit Judge Henry Lackey issued the ruling Wednesday after hearing from election officials who filed the lawsuit.
Plaintiffs say they may appeal the ruling to the Mississippi Supreme Court.
The plaintiffs contended a write-in election would create havoc on election night and makes no provision for determining whether the candidates, or the ultimate winner, would be qualified to be a judge.
The State Election Commission decided to have a write-in election because the only person who signed up to run in the 13th District was incumbent Judge Robert G. Evans. He died of cancer in July, after the candidates' May 7th qualifying deadline.