Burundi President Domitien Ndayizeye has signed a series of laws, creating a new national defense force that includes former rebel fighters.
A presidential spokesman, Pancrace Cimpaye, says since the New Year, the Burundi Armed Forces - as it was formerly called - no longer exists.
The new National Defense Force will have 30,000 troops - evenly split among the nation's minority ethnic Tutsis and majority Hutus. Twenty-thousand officers will make up the new National Police Force - also evenly divided between Tutsis and Hutus.
As part of a peace deal to end Burundi's decade-long war, several former Hutu rebel groups have joined a transitional government designed to end years of dominance by minority Tutsis.
However, Burundi's oldest Hutu rebel group, the National Liberation Forces, continues to fight the government.