The changes to the state's habitual offender law will affect thieves, small-time drug dealers and users.
It will not cover burglary or drug trafficking charges.
Under the old law, two or more prior felonies resulted in longer prison sentences.
Supporters of the law say the change was needed to help reduce over-crowding in the state's prisons.
"Prisons should be reserved for violent offenders and the limited bed space that the Department of Corrections has should go to violent offenders and those who profit off of selling drugs," said Judge Larry Anderson of the 20th judicial circuit.
The guidelines were implemented on a voluntary basis in 2006.
In 2012, Alabama lawmakers agreed to make the guidelines presumptive which means they will be applied unless there are compelling reasons not to.
Some prosecutors and judges say the guidelines take the court's discretion out of the system.