The former Crewe Alexandra coach was serving a 34-year sentence after being convicted of a number of child sex offences.
A spokesman for the Ministry of Justice said: “Prisoner Barry Bennell died at HMP Littlehey on September 16.
“As with all deaths in custody, the Prisons and Probation Ombudsman will investigate.”
Bennell, also known as Richard Jones, was jailed for 30 years in 2018 after being convicted of 52 child sexual offences against 12 boys.
He was ordered to serve an additional four years in 2020 after pleading guilty to other offences against two boys.
When he was sentenced at Liverpool Crown Court in 2018, Recorder of Liverpool Judge Clement Goldstone QC said he “may well die in prison”.
His final prison sentence, in 2020, was the fifth time he had been jailed.
At that hearing, the court was told he had a detached retina after being attacked in prison and was in remission from cancer.
Bennell, a former Manchester City scout, abused boys he coached in the 1970s, 1980s and 1990s.