Rumsfeld said on Thursday he had not yet made a final decision on attending the two-day Munich Conference on Security Policy, but said the lawsuit accusing him of war crimes would certainly influence his ultimate decision.
"It's something that we have to take into consideration," Rumsfeld said."Whether I end up there we will soon know. It will be a week and we will find out."
An address by the US defence secretary is a typical highlight of the annual conference, attended by government defence officials and lawmakers from Europe and elsewhere.
Attorneys from the New York-based Centre for Constitutional Rights filed a suit with German federal prosecutors last November charging that US officials, including Rumsfeld, are responsible for acts of torture against detainees at the Abu Ghraib prison in Iraq.
Rumsfeld has maintained that the US government has no policy to permit or encourage torture and that US investigations of the Abu Ghraib abuses showed he was not directly responsible.
The lawsuit against Rumsfeld was filed in Germany because its laws allow for the prosecution of war crimes and human rights violations across national boundaries.
Because the US is not a member of the International Criminal Court, the case could not be filed there.