German Minister Gives Up Doctorate After Plagiarism Row
Last week Karl-Theodor zu Guttenberg said he would temporarily give up the title while his university investigated the charges.
The University of Bayreuth says he has now asked them to retract his doctorate in law, according to German TV.
Mr Guttenberg admitted that he had made "serious mistakes".
At an election rally near Frankfurt on Monday, the charismatic defence minister said the mistakes were not intentional but he conceded that they "do not meet the ethical code of science".
He said it was a painful decision to make, especially given that he had worked for six or seven years of his life on the PhD.
His thesis - Constitution and Constitutional Treaty: Constitutional Developments in the US and EU - was completed in 2006 and published in 2009.
The Suddeutsche Zeitung claimed that Mr zu Guttenberg had copied, word for word, one passage from a newspaper article and another from a public lecture, without attributing them, while other texts were incorrectly attributed.
The list of alleged instances of plagiarism grew as journalists and internet users looked more deeply at the thesis.
Chancellor Angela Merkel insisted on Monday that she is standing by her defence minister, who is seen as something of a rising star in her conservative coalition.
"I appointed Guttenberg as minister of defence," she told reporters. "I did not appoint him as an academic assistant or doctor. What is important to me is his work as minister of defence and he carries out these duties perfectly."
She also played down the role that the scandal might have played in her party's heavy defeat in a regional election in Hamburg at the weekend.