The bill will go to Idaho Gov. Brad Little's desk next. His office did not immediately respond to a request for comment Tuesday morning.
Four other states have an option for the firing squad, although its use is extremely rare, according to the Death Penalty Information Center.
Bryan Kohberger, right, who is accused of killing four University of Idaho students in November 2022, is led away following a hearing in Latah County District Court, Thursday, Jan. 5, 2023, in Moscow, Idaho. He could face the death penalty if convicted on any one of the four counts of first-degree murder he faces in the deaths of Madison Mogen, Kaylee Goncalves, Xana Kernodle and Ethan Chapin. (AP Photo/Ted S. Warren, Pool)
Those states are Mississippi, Oklahoma, Utah and South Carolina, and together they have killed three condemned prisoners by firing squad since 1976.
Utah brought back firing squads in 2015 due to its own struggles with lethal injections. The practice was legal in Idaho until 2009 but had never been used by the time lawmakers got rid of it.
Idaho currently has eight death row inmates – and prosecutors have not yet ruled out seeking the death penalty in a high-profile quadruple murder case that left four University of Idaho students dead in November.
The execution chamber at the Idaho Maximum Security Institution is shown as Security Institution Warden Randy Blades looks on in Boise, Idaho on Oct. 20, 2011. A bill that would allow Idaho to kill condemned inmates by firing squad is headed to the governor's desk after passing the Legislature with a veto-proof majority. Firing squads will only be used if the state cannot obtain the drugs needed for lethal injections. (AP Photo/Jessie L. Bonner, File)
Rep. Bruce Skaug, a Nampa Republican and also a University of Idaho alumnus, introduced the bill in late February, weeks after police arrested a suspect.
Bryan Kohberger is being held at the Latah County Jail in Moscow on four charges of first-degree murder and another of felony burglary.
Madison Mogen, top left, smiles on the shoulders of her best friend, Kaylee Goncalves, as they pose with Ethan Chapin, Xana Kernodle, and two other housemates in Goncalves' final Instagram post, shared the day before the four students were stabbed to death. (@kayleegoncalves/Instagram)
Kohberger is accused of stalking an off-campus rental home at least 12 times before allegedly sneaking in around 4 a.m. on a Saturday, after the victims had spent the night out partying with friends, then ambushing them with a large knife. Around 9 a.m., hours after the murders but before surviving roommates woke up and called for help, police say he drove by one last time.
Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin all suffered multiple stab wounds, according to the Latah County coroner Cathy Mabbutt. Some of them may have been sleeping at the start of the attack.
Police found a Ka-Bar knife sheath next to Mogen's body that they say had Kohberger's DNA on it.
His next court date was scheduled for June 26, when he is expected to challenge the evidence used to arrest him. He has not yet entered a plea.
Fox News' Paul Best and The Associated Press contributed to this report.