Reinhold Hanning's lawyer confirmed on Thursday that his client had died at his home in Lage, North Rhine-Westphalia on Tuesday.
Hanning was convicted last year for his complicity in the Holocaust, and sentenced to five years in prison. As an SS member and guard at Auschwitz, the court ruled that Hanning had been an accessory to murder in 170,000 cases.
"He was aware that in Auschwitz, innocent people were murdered every day in gas chambers," the court said in the ruling nearly one year ago.
But the conviction had not yet been fully legally binding because an appeal was still set to be heard by the Federal Court of Justice.
According to Bild, Hanning had been living with his son and daughter-in-law and rarely left the house.
During the four-month trial, which involved witnesses giving harrowing accounts of the living hell they faced, prosecutors outlined how Hanning had watched over the selection of prisoners deemed fit for slave labour, and those sent to the gas chambers.
They also accused him of knowing about the regular mass shootings and the systematic starvation of prisoners.
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Hanning had admitted to the court that he knew prisoners were being shot and gassed and that their bodies were burned at the camp, noting that he had been "silent all my life" about the atrocities because he felt deep shame. He added that he had never spoken a word about it to his wife, children or grandchildren.
“I am truly sorry,” he said.
"I deeply regret having listened to a criminal organisation that is responsible for the deaths of many innocent people, for the destruction of countless families, for the misery, distress and suffering on the part of victims and their relatives.
"I am ashamed that I let this injustice happen and did nothing to prevent it.”
Hanning's case was thought to be one of the last such trials of former Nazis.
The legal basis for prosecuting former Nazis changed in 2011 with Germany's landmark conviction of former death camp guard John Demjanjuk.
He was sentenced not for atrocities he was known to have committed, but on the basis that he served at the Sobibor camp in occupied Poland - for having been a cog in the Nazis' killing machine.
The trial against a 96-year-old former SS medic, Hubert Zafke, looks likely to be halted for good after the court announced last month that his dementia has become too severe for him to stand trial.