A former Catholic monk who taught at the Fort Augustus Abbey school has failed in a bid to halt his extradition from Australia.
Fr Denis "Chrysostom" Alexander, 83, had challenged a decision by the Australian Government to surrender him to face trial in Scotland.
But the federal court has now dismissed his case against the attorney general.
Fr Alexander, who featured in a BBC Scotland investigation, denies the allegations.
The 13-page federal court ruling includes a summary of the charges the ex-monk faces.
It is alleged that between 1970 and 1976 he "engaged in acts of physical and sexual abuse" against six complainants, aged between 11 and 15.
The Crown Office launched extradition proceedings against Fr Alexander in December 2016 but since then he has contested the move on health grounds.
A letter from his solicitors in November 2017 stated that he suffers from "several chronic and ongoing health problems" and that travel to the UK "presents a real risk of serious injury and further significant ongoing deterioration of Mr Alexander's health, including death."
Fr Alexander, who turns 84 next month, was arrested in Sydney almost three years ago and has been in custody ever since.
It is understood he has 28 days to appeal the federal court's decision.
The Crown Office said extradition proceedings are "ongoing".
July 2013: BBC airs Sins of Our Fathers, revealing decades of sexual and physical abuse at the Fort Augustus Abbey School and Carlkemp preparatory school, and confronts Fr Alexander in Sydney
December 2015: The Crown announces plans to extradite Fr Alexander back to Scotland
January 2017: Fr Alexander is arrested in Sydney and remanded in custody
May 2017: Fr Alexander is found eligible for extradition by an Australian court. He appeals, claiming he is too ill to travel
March 2019: The attorney general of Australia determines that Fr Alexander be surrendered to the UK. Fr Alexander seeks a judicial review
November 2019: The federal court of Australia dismisses Fr Alexander's application for a judicial review.
Run by Catholic Benedictine monks, Fort Augustus Abbey school in the Highlands closed its doors to the public in 1993.
Allegations of decades of child sexual and physical abuse at the exclusive boarding school were finally made public by BBC Scotland Investigations Correspondent Mark Daly in June 2013.
He spoke to former pupils who claimed they were abused by monks or teaching staff over five decades.
Many of those then reported their allegations to the police, sparking a major historical abuse police inquiry.