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
British Bankers' Association head Anthony Browne warned that some banks could be moving abroad within weeks due to Brexit uncertainty.
Labour said its plan would mean grieving families would not have to pay for either a burial plot or cremation for a child aged under 16.
The children are among around 70 new young arrivals to arrive in Britain under the landmark Dubs amendment.