A deal has been signed that could see convicts found guilty of involvement in the 1994 genocide by a UN-backed tribunal serving their time in Rwanda.
More than 800,000 people died in the 1994 genocide
The agreement ends three years of negotiations between Rwanda's government and the International Criminal Tribunal for Rwanda (ICTR).
Thirty of 56 prisoners detained by the tribunal in Tanzania have protested, saying they fear torture or death.
Some 800,000 Tutsis and moderate Hutus were killed in the 1994 genocide.
The ICTR was set up in the Tanzanian town of Arusha in 1997 to try the most high-profile genocide cases.
The deal came after an inspection by the ICTR found Rwandan prisons met international standards.
Negotiators say it is a landmark deal
ICTR registrar Adama Dieng said the accord was a milestone in relations between Rwanda and the ICTR.
The BBC's Geoffrey Mutagoma in Rwanda's capital, Kigali, says the relationship has in the past been characterised by on-off misunderstandings and judicial and procedural disagreements.
Our correspondent says there was no mention of when the prisoners will be transferred to Rwanda which is now one of seven eligible countries where ICTR prisoners can serve their terms.
Rwanda has long been pushing for genocide convicts to serve their sentences at home where their crimes were committed.
Last year, Rwanda abolished the death penalty so countries that object to capital punishment are able to extradite genocide suspects directly to Rwanda to face justice.
Rwandan Foreign Minister Charles Muligande, who attended the signing ceremony, says the government has requested that the ICTR hand over all its archives at the end of its mandate in 2010.
Meanwhile, Rwandan MPs have expressed anger over the arrest warrants recently issued by Spanish judge Fernando Andreu for 40 Rwandan army officers on genocide charges.