Steven Palazzo has defeated Joe Tegerdine in south Mississippi's 4th District Republican congressional primary.
Unofficial results Tuesday show Palazzo with strong showings in some of the larger counties, including his home of coastal Harrison County.
Palazzo is a military veteran, certified public accountant and first-term state lawmaker from Biloxi.
Tegerdine, a businessman from Petal, courted tea party voters in his first run for office.
Democrat Gene Taylor of Bay St. Louis has represented south Mississippi in the U.S. House since 1989.
The November ballot will have Taylor, Palazzo, a Libertarian and a Reform Party candidate.