Armen Meiwes was given an eight and half-year prison sentence for manslaughter by a court in the town of Kassel in January 2004.
In the new trial, to begin on Thursday, prosecutors will seek to upgrade the conviction to one of murder.
Meiwes admitted killing and eating a 43-year old engineer, Juergen Brandes who had responded to an Internet advertisement, posted by Meiwes under the pseudonym Franky.
However, a federal tribunal upheld state prosecutors' appeal last April, calling the verdict too lenient, and ordered a new trial before the regional court in Frankfurt.
Prosecutors are seeking a life sentence.
Judges will now have to decide whether Meiwes is guilty of murder or the lesser charge of "killing on demand" by slaughtering and eating a volunteer.
The federal court said when it accepted the appeal that because Meiwes had made a videotape of the act with the aim of producing pornography for himself and others, the killing likely qualified as "murder for sexual gratification".
Meiwes, a 44-year old technician from the town of Rotenburg, has said he deeply regrets his crime.
He said to the Times: "He built up a fantasy world on the internet and then it suddenly became real. He is fighting against those fantasies and wants therapy. He wants to start a normal life afterwards."
In an interview published in London's Times newspaper he said: "I understand and regret deeply what I did, but the victim wanted me to do it. Otherwise I would never have touched him."
"He built up a fantasy world on the internet and then it suddenly became real"
Gunther Stampf, German film maker
He said he would have preferred it if Brandes had killed himself and declined to comment on whether he would commit such an act again.
Brandes travelled to Rotenburg, leaving a will, after posting his own Internet advertisement as a willing sacrifice. He met Meiwes in early 2001 when they performed a series of gratuitous acts before the latter killed him and ate around 20kg of his flesh.
Library of information
Meiwes searched for further victims until December 2001 when a student tipped police off and he was arrested.
The detailed and gruesome insights into Meiwes' fetishism shocked Germany. He had 16 computers with 2000 disks full of information about Germany's secret cannibal underworld. He had allegedly been in contact with more than 200 people, most of whom wanted to be killed and eaten, or tortured.
Günter Stampf, a German film maker who conducted the interview with Meiwes in jail, said Meiwes had admitted he still had fantasies about cannibalism.