Judges at the Karlsruhe court rejected his appeal on October 7, but only made their decision public on Friday.
Meiwes made international headlines when news of the grisly incident in the German state of Hesse spread. After meeting a 43-year-old engineer from Berlin online, he and his victim agreed to the killing.
Meiwes then built a "slaughter room" in his Rotenburg home and videotaped the bloody deed to have the images later for his sexual satisfaction.
Meiwes can be released "in 15 years at the earliest" and "only if he is no longer dangerous," the court said.