The Revolutionary Armed Forces of Colombia or FARC, is at its weakest in decades after the government launched a US-backed military crackdown. Rebels have lost several top commanders in the last few years as troops drove them back into remote jungles and mountains.
Mono Jojoy, who was often seen wearing his trademark black beret, was considered the FARC's top military chief. The FARC's founder, Manuel Marulanda, died in 2008 and two other commanders were killed that year, one by his own bodyguard.
The rebel chief, known also as Jorge Briceno, was killed in an air strike in the Macarena region, one of the FARC's last strongholds, the army and local Caracol radio said.
Once branded as a failing state, Colombia has seen bombings and kidnappings from its long war ebb and foreign investment has grown fivefold since 2002, when former President Alvaro Uribe began a hard-line campaign against the rebels.
President Juan Manuel Santos, a former defense minister, has promised to keep up Uribe's tough line, dismissing any possibility of talks with the FARC unless the rebels cease hostilities and release hostages they are holding.
Started as a peasant army in the 1960s, the FARC grew into a powerful force that controlled large parts of Colombia and kidnapped and bombed at will. But rebels have little political support and rely on cocaine trafficking to support their network, often in league with criminal gangs.
