State Republican Party Chairman Mark Amodei is joining the race for Nevada's 2nd Congressional District.
Amodei has been mulling the race for weeks and has scheduled a 10 a.m. news conference in Carson City.
He will join three other Republicans who have announced their intent to try to win the seat left open by Rep. Dean Heller, who is being sworn in Monday as Nevada's newest U.S. senator.
Heller's replacement will be chosen in a special election Sept. 13.
Other Republicans who say they'll run include Sharron Angle, who lost a U.S. Senate bid last fall to Democrat Harry Reid; former USS Cmdr. Kirk Lippold; and state Sen. Greg Brower.
State Treasurer Kate Marshall and fellow Democrats Jill Derby and Nancy Price also say they'll run in the special election.