The lawsuit charges that officials at the highest levels of the US government shoulder ultimate responsibility for the physical and psychological injuries sustained by the men while in American custody.
It was the latest development in a scandal over ill-treatment of US war prisoners that has drawn criticism from around the world.
The case will be filed on Tuesday by the American Civil Liberties Union and Human Rights First in US District Court. The two groups scheduled a news conference later on in the day to announce details.
The groups did not state who would be named in the lawsuit, but sources familiar with the case said it was Rumsfeld.
"The men represented in the lawsuit were incarcerated in US detention facilities in Iraq and Afghanistan, where they were subjected to torture and other cruel and degrading treatment, including severe and repeated beatings, cutting with knives, sexual humiliation and assault, mock executions, death threats, and restraint in contorted and excruciating positions," the two groups said in a statement.
"The men... were subjected to torture and other cruel and degrading treatment, including severe and repeated beatings"
Statement by US Human Rights Groups
None of the eight men was charged with a crime, the groups said.
Bill Lann Lee, an assistant US attorney general for civil rights during the Clinton administration, and retired Rear Admiral John Hutson, former judge advocate general of the US Navy, were due to participate in the news conference.
This is not the first legal case over detainee abuse involving Rumsfeld.
US human rights lawyers filed a criminal complaint in November with Germany's federal prosecutor charging that Rumsfeld, former CIA Director George Tenet and other senior officials bore responsibility for detainee abuse at Abu Ghraib prison in Iraq.
The case was filed in Germany because its laws permit prosecution of war crimes and human rights violations across national borders. German officials on 10 February said they would take no action against Rumsfeld in the case.
An August 2004 report by a four-member panel appointed by Rumsfeld stated that he and other top Pentagon leaders contributed to an environment in which prisoners suffered sadistic abuse at Abu Ghraib.
A panel said the Pentagon
allowed abuse at Abu Ghraib
The report said changes made by Rumsfeld in prisoner interrogation methods at the US naval base at Guantanamo Bay, Cuba, contributed to uncertainty in the field as to what actions were allowed and what were not.
Many detainees in the US war against international terrorism are held at Guantanamo.
The mistreatment of prisoners became an international scandal after the appearance last year of pictures showing sexual abuse of men - naked and bound - at Abu Ghraib.
The administration led by President George Bush says only a handful of low-ranking personnel were involved.
Dozens of other cases have been brought against soldiers for abusing detainees elsewhere in Iraq and in Afghanistan.