Colorado is set to become the 22nd U.S. state to abolish the death penalty.
Lawmakers gave final approval to a bill to end the practice Wednesday, and the state's governor has said he will sign it.
Proponents of halting the use of the death penalty argued it is a punishment that cannot be reversed if later evidence emerges showing someone is innocent, and that it is disproportionately applied to minorities and the poor.
Those who wanted to keep capital punishment as a sentencing option said the threat of the death penalty gave defendants incentive to seek agreements to plead guilty to crimes and accept lower sentences instead of going through a lengthy trial.
Colorado has three people on its death row. The new law will not affect their sentences, only new offenses starting in July.
The state last executed someone in 1997. Nationally, there have been four executions this year.
Last year, the state of New Hampshire abolished the death penalty, while California Governor Gavin Newsom said last year there will be no capital punishment while he is in office.