At least 180,000 have died and 2 million have been displaced in violence that has raged since February 2003.
"The investigation will be impartial and independent, focusing on the individuals who bear the greatest criminal responsibility for crimes committed in Darfur," the ICC said in a statement, according to Reuters.
In April, in a move meant partly to pressure the Sudanese government into ending the Darfur conflict, the U.N. Security Council referred the case to the ICC. As part of the referral, U.N. Secretary-General Kofi Annan gave the court a sealed list of 51 people accused of crimes against humanity.
Although the names of those listed have not been revealed, the list is expected to include Sudanese government officials, rebels and members of the ethnic Arab Janjaweed militia accused of having government backing to rape, murder and burn villages in Darfur.
"The wheels of justice are finally beginning to turn on behalf of the people of Darfur who have been victims of mass slaughter, widespread rape and forced displacement," said Richard Dicker, a spokesman for Human Rights Watch.
ICC chief prosecutor Luis Moreno-Ocampo called on national and international parties to cooperate with the investigation.
"It will form part of a collective effort, complementing African Union and other initiatives to end the violence in Darfur and to promote justice," he said.
The 53-nation African Union, which has led efforts to bring the Sudanese government and rebel fighters together for peace talks, currently has about 2,300 troops deployed in Darfur. Though talks scheduled for May 30 were delayed, both sides have agreed to resume negotiations June 10.
Sudanese officials are opposed to the ICC investigation. The government claims to have already arrested members of the military and security forces and says it will prosecute any war crimes at home, Reuters reported.
"The priority of the international community should be to secure a cease-fire in which people could trust for the rendering of justice," Najeeb al-Kheir Abdul Wahab, Sudan's state minister for foreign affairs, said following the ICC announcement.
Rebel leaders, on the other hand, say they welcome the Security Council referral and have said they plan to turn over any members indicted by the court.
The United Nations has called the conflict in Darfur and the resulting civilian deaths from violence, hunger and disease, one of the world's worst humanitarian crises. The United States has termed the conflict genocide.