(730 ILCS 5/3-3-3) (from Ch. 38, par. 1003-3-3)
    Sec. 3-3-3. Eligibility for parole or release.
    (a) Except for those offenders who accept the fixed release date established by the Prisoner Review Board under Section 3-3-2.1, every person serving a term of imprisonment under the law in effect prior to the effective date of this amendatory Act of 1977 shall be eligible for parole when he or she has served:
        (1) the minimum term of an indeterminate sentence
    
less time credit for good behavior, or 20 years less time credit for good behavior, whichever is less; or
        (2) 20 years of a life sentence less time credit for
    
good behavior; or
        (3) 20 years or one-third of a determinate sentence,
    
whichever is less, less time credit for good behavior.
    (b) No person sentenced under this amendatory Act of 1977 or who accepts a release date under Section 3-3-2.1 shall be eligible for parole.
    (c) Except for those sentenced to a term of natural life imprisonment, every person sentenced to imprisonment under this amendatory Act of 1977 or given a release date under Section 3-3-2.1 of this Act shall serve the full term of a determinate sentence less time credit for good behavior and shall then be released under the mandatory supervised release provisions of paragraph (d) of Section 5-8-1 of this Code.
    (d) No person serving a term of natural life imprisonment may be paroled or released except through executive clemency.
    (e) Every person committed to the Department of Juvenile Justice under the Juvenile Court Act of 1987 and confined in the State correctional institutions or facilities if such juvenile has not been tried as an adult shall be eligible for aftercare release under Section 3-2.5-85 of this Code. However, if a juvenile has been tried as an adult he or she shall only be eligible for parole or mandatory supervised release as an adult under this Section.
(Source: P.A. 98-558, eff. 1-1-14; 99-628, eff. 1-1-17.)