Colombian Red Cross officials say they have recovered 11 bodies following a tip-off from Revolutionary Armed Forces of Colombia (Farc) rebels.
In April, a video of the hostages was aired on Colombian TV
It is thought that the 11 are all lawmakers, killed three months ago while being held hostage by the rebels.
The International Committee of the Red Cross said in a statement that the Farc had given them co-ordinates to where the corpses lay in an undisclosed area.
The bodies were flown to the city of Cali for a forensic examination.
Family members were present when the bodies arrived at the mortuary.
"I never imagined this end," said Fabiola Perdomo, wife of one of the lawmakers. "I always thought I would see [my husband] returning alive."
The lawmakers were kidnapped five years ago when guerrillas dressed as soldiers attacked the state legislature in the southern city of Cali.
The Farc announced in June that the hostages had been killed when an unidentified military group attacked the jungle base where they were being held.
The government denied attempting a rescue and initially accused the rebels of executing the hostages.
It later said they died in a mistaken clash between two guerrilla groups.
It is hoped that the forensic examination will not only identify the bodies, but also confirm whether the 11 did indeed die in a shoot-out or were executed.
The Farc are still holding a number of other hostages, including former presidential candidate Ingrid Betancourt, who holds dual Colombian-French citizenship.
Venezuela President Hugo Chavez was recently asked to mediate between the Farc and the government of President Alvaro Uribe.
The BBC's Jeremy McDermott in Medellin says the Farc have never hidden their admiration for the controversial Venezuelan leader and if anyone can prompt them to make concessions, it's him - but it comes too late for the murdered politicians.