Knox and Sollecito's orginal sentences of 28 years and six months in jail and 25 years respectively were upheld. The new verdict in the long-running case following the former loverssuccessful 2011 appeal, in which they were set free from the sentences. The move, in Florence, follows a retrial for murder of Ms Kercher, who was found stabbed to death in the house she rented in Perugia in November 2007.
Neither Knox or Sollecito were in court for the decision.
The verdict confirms an original 2009 conviction, and sentences Knox to serve 28 years and six months in jail. Sollecito was sentenced to 25 years.
Knox is in the United States and any detention would depend on the outcome of yet another appeal and she would have to be extradited to serve the sentence.
Sollecito is free pending a definitive confirmation of the verdict by Italy's highest court but cannot travel out of the country.
Miss Kercher, a 21-year-old Leeds University student from Coulsdon, Surrey, was found with her throat slashed. Prosecutors claimed that Miss Kercher was the victim of a drug-fuelled sex game gone awry. Knox and her former boyfriend Sollecito have consistently protested their innocence and claim they were not even in the apartment on the night Miss Kercher died. Knox was convicted of the murder in December 2009 along with Sollecito following a high-profile trial, with Knox sentenced to 26 years in prison and Sollecito 25. The pair were later cleared in 2011 after an appeal court found the prosecution lacking and criticised large swathes of the case against them. Italy's highest criminal court, the Court of Cassation, ruled last March that an appeal court in Florence must re-hear the case against Knox and Sollecito for the murder. Knox, who now lives in Seattle, said she would not attend due to being unable to afford to travel to Italy and remained in the US for the duration of the retrial.