Some 30 plaintiffs -- mainly concentration camp survivors and their relatives -- are charging the Ukrainian-born man with assisting in the murder of 27,900 people at the Sobibor concentration camp between March and September 1943. If convicted, he could be sentenced to 15 years in prison.
Held in a Munich court, the proceedings are making waves because of Demjanjuk's poor health. The trial resumed this week after a three-week adjournment so that Demjanjuk could recover from an infection. The presiding judge has limited the proceedings to two 90-minute sessions per day, and Demjanjuk is attending them lying in a hospital bed.
The defendant was born in Ukraine and fought in the Soviet army when he was captured by the Nazis. He was then recruited and trained as a camp guard, where he claims he worked in several camps, but not Sobibor as alleged.
In 1993 Demjanjuk was cleared by an Israeli court of being a notorious Treblinka guard called Ivan the Terrible.
Yet there exists an ID identifying him as one of the guards at Sobibor, where around 250,000 Jews died during the Nazi era. Demjanjuk was one of the Simon Wiesenthal Center's most-wanted war criminals.
After World War II Demjanjuk immigrated to the United States, where he worked in the car industry near Cleveland, Ohio, before authorities extradited him to Germany.
The court Tuesday heard relatives of people who died in the gas chambers of Sobibor.
"The Ukrainian guards were worse than the SS," said Jules Schelvis, 88, whose wife and 18 relatives were gassed in Sobibor. "I couldn't greet or kiss her anymore."
The proceedings will resume Jan. 12. A verdict is expected around May, but the outcome is less than obvious, experts say.
"Even though we know what happened at Sobibor, the problem is that this crime -- the Holocaust -- simply can't be dealt with by our judicial system," Angelika Benz, a history expert following the trial, told Deutsche Welle. "This becomes clear when we're dealing with someone like Demjanjuk, about whom we know very little."