Jammeh accepting defeat sparked wild celebrations in a country he has ruled with an iron hand since taking power in a coup 22 years ago.
Jammeh's statement on state radio sparked wild celebrations in a country he has ruled with an iron hand since taking power in a coup 22 years ago, but doubts persisted over how he would step aside and whether the army would switch its allegiance.
Gambia lacks a formal timetable for the handover of power and Jammeh has not been seen publicly since the announcement of the election results, which showed his challenger Adama Barrow comfortably ahead.
"We want to get a cabinet in place and it all starts from there. We want reforms," Barrow told Reuters at his home where hundreds of supporters had gathered to shake his hand. He said he had yet to meet army leaders but hoped to do so soon.
Jammeh led a government accused of crushing dissent and torturing opponents. He had said he would rule for a "billion years" and few believed he would allow himself to lose Thursday's vote.
But in an address on state-owned radio on Friday evening, he accepted the official results, stunning observers across Africa.
The continent's entrenched rulers such as Jammeh rarely lose elections so the result came as a shock, particularly given that other African leaders have since last year changed their country's constitutions to prolong their rule.
The official results in the West African country of 1.8 million gave Barrow, a real estate developer who once worked as a security guard at retailer Argos in London, 45.5 percent of the vote against Jammeh's 36.7 percent.