Illinois' death penalty ban, signed by Governor Pat Quinn in March, will go into effect on Friday.
The change makes Illinois the fourth state since 2007 and fifteenth U.S. state overall to abolish capital punishment.
Quinn commuted the sentences of 15 prisoners held in death row at Pontiac Correctional Center just days after signing the measure, trying to avoid the inconsistency of a death penalty ban for future crimes and having prisoners slated for execution with the bill already signed and waiting to go into effect.
The death penalty has been avoided in Illinois for more than a decade, stemming from former Gov. George Ryan's moratorium on executions in 2000 and his commuting of more than 160 death sentences in 2003.
The Illinois House approved the measure in early January, with the state Senate following suit a few days later. Chicago Democrat Sen. Kwame Raoul sponsored the bill, which also received verbal support from then mayor-elect Rahm Emanuel at the time of Quinn's signing.