The case of sexually-inspired cannibalism is so extraordinary it is expected to make legal history.
Meiwes, 42, described by his lawyer as a "gentleman of the old school", has confessed to killing a Berlin man who answered an advertisement he had posted on the Internet seeking a fit man "for slaughter."
They met in Meiwes's elegant half-timbered home in the town of Rotenburg, central Germany, in March 2001.
Meiwes killed the man, named only as Bernd-Juergen B., with a kitchen knife and filmed the deed on video tape which may be shown at the trial.
Bled to death
Meiwes' lawyer Harald Ermel said it took the victim nearly 10 hours to bleed to death and that he had repeatedly urged Meiwes to keep on cutting him.
Meiwes cut up the body and stored parts in his freezer. "He believes he ate about 20 kg and there were about 10 kg left over," said Ermel.
"He defrosted it little by little and ate it."
Police arrested Meiwes over a year later, in December 2002, after a tip-off from someone who had spotted another of his adverts on the Internet.
Meiwes is expected to repeat his confession at the trial that will be attended by reporters from all over the world. He is already planning to write his memoirs, his lawyer said.
"He defrosted it little by little and ate it"
lawyer for Meiwes
Meiwes told German newspaper Welt am Sonntag last week: "I am guilty and regret what I did." He said he had eaten his victim because he wanted to make him part of himself, a desire that he had satisfied and that would not recur.
Professor Andreas Marneros, director of the Halle Clinic for Psychiatry and Psychotherapy, said: "This is cannibalism as a sexual perversion, it's a phenomenon that has been known about for centuries. I have examined four such people."
Prosecutors in the city of Kassel say a psychiatric examination found Meiwes is not insane but they added that his victim may have been incapable of rational thought.
So while prosecutors acknowledge the victim said he wanted to die, they are seeking a life sentence on a charge of murder motivated by sexual urges.
Meiwes's lawyer wants him to be convicted of "killing on request", a form of illegal euthanasia which carries a sentence of six months to five years.
The problem, legal experts say, is that Meiwes's victim wanted to be eaten. That could make a murder charge difficult to apply, while the lesser charge of manslaughter carries a term of 15 years or considerably less, after which Meiwes would be free.
"This is cannibalism as a sexual perversion, it's a phenomenon that has been known about for centuries"
Prof. Andreas Marneros,
director, Halle Clinic for Psychiatry and Psychotherapy
Professor Arthur Kreuzer of the Institute for Criminology at Giessen University, said the case might make legal history.
"This is killing undertaken for both killer and victim and cannot be regarded as the worst case of premeditated killing. But I don't think it is a killing on request either because it was not an altruistic, but an egoistic deed," Kreuzer said.
He said the case may go as high as the Federal Constitutional Court and that prosecutors may be forced to consult new medical experts to assess Meiwes's mental state.
Meiwes's lawyer has revealed that his client had four other guests in his home, but let them all go.
"There was a teacher, a cook, a hotel employee and a student. He had them hanging from the ceiling head down and they had no chance of freeing themselves. One felt sick, the other didn't want to go on, he let them all down."
Ermel said Meiwes chatted about cannibalism with at least 280 like-minded people on the Internet. In Germany about 200 people on the Internet were offering to be slaughtered, 30 ready to do the slaughtering and 10 to 15 wanting to watch, he said.