Standing next to Guillaume Soro, the prime minister and former leader of the Forces Nouvelles (FN), a rebel group, Laurent Gbagbo, the president, said: "There is no more battle-front in Ivory Coast."
The ceremony was held on Saturday in the central market town of Tiebissou, within the former buffer zone separating the north and south and monitored by international peacekeepers since the end of the 2002 war.
Describing the disarmament process involving FN forces and pro-government fighters as the "last segment" of the March peace accords, Gbagbo said: "I really hope elections will take place at the end of June.
"We are galloping towards the elections."
A peace treaty signed in March in Burkina Faso - one of several signed by the two sides to reunite the country - called for holding presidential elections in 2008 and gave a general timeline for disarming militias and FN forces.
Gbagbo's mandate officially expired in 2005, but he has remained in power, with proposed elections pushed back several times.
Like other parts of the Ouagadougou agreement, the disarmament process has been delayed.
The two sides previously hosted two disarmament ceremonies in the western town of Guiglo in May, and the northern rebel stronghold of Bouake in July.
But the next step in the process - full disarmament, demobilisation and reintegration of former fighters into the government forces - were not taken.
The two sides signed a new agreement in November on regrouping their forces, withdrawing and stocking weaponry and dismantling armed groups as of December 22.
The process will be overseen by a command centre based in Yamoussoukro, the political capital, under the supervision of UN peacekeepers and French troops under Operation Licorne (Unicorn).
The latest agreement also provides for the extension of a government administration across the country to be completed at the latest on January 30, 2008.
In addition, ex-fighters are to benefit from a job-training programme to be launched in January and an allowance for the first three months of the disarmament process.