Prison medical staff tried to revive Ariel Castro after he was found hanging in his prison cell but failed, according to CNN.
Castro was taken to The Ohio State University Wexner Medical Center where he was pronounced dead at 10.52pm local time.
Castro's brother-in-law, Juan Alicea, told CNN that the family was notified by a warden at about 1 am.
More top news
Charlton Athletic were left red-faced when the club showed a face of Alan Campbell during a minute's applause for Graham Moore.
A global unemployment rate of 50% is possible as job vacancies are filled by machines, according to scientist Moshe Vardi.
A British teenager arrested in connection with cyber-crime offences is suspected of hacking an email account used by the head of the CIA.