Cuyahoga County Judge Michael Russo imposed the prison sentence after an emotional court hearing at which one of Castro's victims, Michelle Knight, 32, said the former school bus driver put her through a life of hell.
"I served 11 years of hell. Now your hell is just beginning," Knight said of Castro in a statement read to the court.
Castro pleaded guilty last week to hundreds of criminal charges to avoid the possibility of the death penalty.
Wearing leg shackles and dressed in an orange prison jumpsuit, Castro listened to her testimony without expression.
Amanda Berry, 27, Gina DeJesus, 23 and Knight, all went missing from the west side of Cleveland between 2002 and 2004. They were discovered on May 6 after neighbours heard Berry's cries for help from Castro's home.
Cleveland kidnapper Ariel Castro admitted at the hearing on Thursday that he was a sick man but said he is not the monster described by prosecutors.
Castro delivered a rambling statement to the court that he makes no excuses for his behaviour, which he said was "wrong."