UFC 43: Meltdown was a mixed martial arts event held by the Ultimate Fighting Championship on June 6, 2003, at the Thomas and Mack Center in Las Vegas, Nevada.

The event was broadcast live on pay-per-view in the United States, and later released on DVD.

Headlining the card was an Interim Light Heavyweight Championship match between future UFC Hall of Fame inductees Randy Couture and Chuck Liddell.

This was the first interim title fight in UFC history.

Ken Shamrock was originally slated to face Ian Freeman at this event, but was forced from the card with a torn ACL.