Ernst Tremmel had been accused of 1,075 counts of accessory to murder for his time working at the death camp in German-occupied Poland from November 1942 to June 1943.
The trial was to have started next Wednesday in the western city of Hanau, with plans to hear the testimony of Auschwitz survivors.
“All the appointments related to these proceedings have now been cancelled,” the regional court in Hanau said in a brief statement.
No cause of death was released.
Tremmel served with an SS Totenkopf unit processing the arrival of prisoners and was allegedly directly involved in three transports, from Berlin, the French city of Drancy and Westerbork in the Netherlands.
“Among the deportees, at least 1,075 people were cruelly murdered immediately after their arrival at Auschwitz,” the Hanau court said when it announced the trial in February.
Because Tremmel was aged 19 to 20 at the time of his alleged crimes, he was to have been tried under juvenile criminal law despite his advanced age.
Due to his frail health, the court had ordered hearings to be limited to four hours per day.
The legal foundation for prosecuting ex-Nazis changed in 2011 with the German conviction of former death camp guard John Demjanjuk, solely on the basis of his having worked at the Sobibor camp in occupied Poland.
Tremmel was initially one of 14 suspects targeted in coordinated raids by German authorities in February 2014 in a twilight bid to bring the last living perpetrators of the Holocaust to justice.
Last July, Oskar Groening, dubbed the “Bookkeeper of Auschwitz”, was sentenced to four years in prison for being an accessory to the murders of 300,000 people at the camp.
But the trial of a former Auschwitz medic in the eastern town of Neubrandenburg, 95-year-old Hubert Zafke, on charges of abetting 3,681 murders, was suspended for the second time last month due to his ill health,
raising questions over whether the case can proceed.
A third man, former SS guard Reinhold Hanning, 94, went on trial on February 11 accused of complicity in 170,000 deaths at Auschwitz.
Further investigations are ongoing.
One million European Jews died between 1940 and 1945 at Auschwitz before it was liberated by Soviet forces.