Judge John O'Meara's order says the state has until January 31st to send him a plan for how it plans to deal with those inmates sentenced as juveniles to life in prison.
It must ensure every inmate sentenced to mandatory life as a juvenile has a "fair, meaningful, and realistic" opportunity for parole.
State Attorney General Bill Schuette has argued a U.S. Supreme Court decision that struck down Michigan's juvenile lifer law and others like it should only apply to current and future cases.
Schuette could try to appeal Judge O'Meara's order.
