Ronald Eagles, of Viking, Bracknell, was sentenced at Reading Crown Court on May 2 after being convicted of two rapes and two indecent assaults against two girls during the 1970s and 1980s.
Eagles was arrested on June 11last year and was charged with the offences on November 5.
He pleaded guilty to all of the offences at a hearing at the same court on March 31and was remanded in custody until his sentencing.
Speaking following the sentencing, investigating officer Det Con Eddie Hurley, of the Child Abuse Investigation Unit, said: “I would like to thank the victims for supporting the prosecution in what must have inevitably been an extremely difficult time for them to recall.
“This sentence demonstrates that all sexual offences, including those which are historic, are taken extremely seriously by Thames Valley Police and are handled with the utmost sensitivity to ensure every effort is made to provide a resolution for the victims.
“I would also like to thank the officers who worked on this complex case in which the offences dated back more than 20 years.”