Aid worker Gauthier Lefevre, kidnapped in Sudan's Darfur region, was released today, after 147 days in captivity, a spokesman for the International Committee of the Red Cross said.
Mr Lefevre, who has dual French and British nationality, was the last foreign hostage being held in the region.
"We are extremely happy that he has been released. This has been the longest kidnapping in the recent history of Darfur," ICRC spokesman Saleh Dabbakeh said.
The ICRC suspended its activities in the region following Mr Lefevre's kidnap and that of another ICRC aid worker from eastern Chad which borders Darfur.
"We hope this does not happen again because the biggest losers are the people who have been affected by the armed conflict in Darfur," Mr Dabbakeh added.
Kidnappings of foreign aid workers in Darfur were rare until last year's International Criminal Court arrest warrant for President Omar Hassan al-Bashir, accused of war crimes in Darfur.
Sudan rejects the ICC and Bashir is running for re-election in April's first multi-party elections in 24 years. The United Nations estimates some 300,000 people died in Darfur's humanitarian crisis, sparked by a 2003 rebellion and a government counter-insurgency campaign.
The world's largest humanitarian operation was established to help the more than two million people driven from their homes by the fighting but, following the ICC arrest warrant, Mr Bashir expelled 13 aid agencies.
After reports that ransoms had been paid for some of the foreign aid workers taken hostage over the past year in Darfur, kidnappings became more common. But Sudan has denied paying any ransoms, saying it had given money to tribal elders just to facilitate mediation efforts.
Reuters