The former state senator told the Las Vegas Review-Journal Wednesday that he would seek the seat. He could not immediately be reached for comment.
Republican National Committee representative Heidi Smith confirmed to The Associated Press that Amodei will make a formal announcement later this week.
Amodei's entry marks the start of what could be Nevada's most watched primary in 2012.
Tea party favorite Sharron Angle and retired Navy Cmdr. Kirk Lippold are already running for the seat.
Lt. Gov. Brian Krolicki is also eyeing the seat, but he has said he will not make an announcement until after the Nevada legislative session closes in June.
Heller is running for the U.S. Senate.