The New York-based rights organisation profiles 11 al-Qaida suspects being detained without concern for their rights under international law in a 46-page report.
Titled The United States' Disappeared: The CIA's Long-Term Ghost Detainees, the document describes how the CIA is holding al-Qaida suspects in secret locations, reportedly outside the United States.
These detainees are denied communication with their families, access to the International Committee of the Red Cross or oversight of any sort of their treatment, and in some cases, there is no acknowledgement that they are even being held.
They include Khalid al-Shaikh Muhammad, the suspected architect of the 11 September attacks; Abu Zubaida, reputedly a close aide of al-Qaida chief Usama bin Ladin; Ramzi bin al-Shaiba and Hambali, an alleged al-Qaida ally in Southeast Asia.
Some, such as Muhammad, are reported to have been tortured in custody.
"Those guilty of serious crimes must be brought to justice before fair trials," Reed Brody, special counsel with Human Rights Watch, said in a statement, adding that if the United States ignores international law, "it abandons its ideals and international obligations and becomes a lesser nation."
The rights group said international treaties ratified by the United States prohibited holding prisoners incommunicado and in secret locations.
The Geneva Conventions require that the International Committee of the Red Cross have access to all detainees and that information on them be provided to their relatives.
"Disappearances were a trademark abuse of Latin American military dictatorships in their 'dirty war' on alleged subversion. Now they have become a United States tactic in its conflict with al-Qaida"
Human Rights Watch special counsel
Under international human rights law, detainees must be held in recognised places of detention and be able to communicate with lawyers and family members, it said.
Brody said: "Disappearances were a trademark abuse of Latin American military dictatorships in their 'dirty war' on alleged subversion.
"Now they have become a United States tactic in its conflict with al-Qaida."
US officials say the detentions are essential to confronting terrorism and that many of those held have provided valuable intelligence that has foiled planned attacks.
Human Rights Watch called on the United States to grant unrestricted access to the International Committee of the Red Cross to all detainees held in anti-terrorist operations.