For their decision The Supreme Court held the previous ruling that Kercher had been killed by more than one person in a "sex game gone wrong" and overturned Knox and Sollecito's acquittal citing that there had been "deficiencies, contradictions and illogical" conclusions during the trial that set them free.
Knox, 25, and Sollecito 29, where initially convicted for Kercher's murder in 2009, but a Perugia appeals court acquitted them two years later claiming there were gaps and mishandling of evidence in the case presented by the prosecution. The two spent almost four years in prison before their acquittal.
A third man, Rudy Guede, was also convicted for the slaying of Kercher in a separate proceeding and was sentenced to 16 years in prison.
In the 74-page ruling, Italy's Supreme Court said they "had to recognize that [Guede] was not the sole author" of the crime.
Knox, who currently lives in Seattle, Washington, and Sollecito were ordered back to Italy for a retrial.
During a May interview on the "Today" show, Sollecito said he was not afraid to be retried because he believed in the power of his and Knox's innocence.
“I'm innocent, and we got evidence of our innocence, so we will fight until the end without any worry," he said.