The journalists, Jean-Philippe Remy, Africa bureau chief for French daily Le Monde, and British photojournalist Phil Moore, were arrested on Thursday afternoon.
15 others were also held in the police raid.
Both journalists have covered the region for years winning several awards for their work. Their arrest sparked widespread condemnation from rights groups and diplomats.
"They were released, no charges were brought against them," French ambassador Gerrit Van Rossum said.
However, neither have given their equipment and notebooks back.
Burundi has been in crisis since April when President Pierre Nkurunziza ran for a controversial third term, sparking street protests, a failed coup, regular killings and a nascent rebellion.
Despite Burundi's rejection, African leaders are expected to vote at AU headquarters in Ethiopia this weekend on sending 5,000 peacekeepers to Burundi, to end months of the violence the journalists were reporting on when arrested.
The Foreign Correspondents' Association of East Africa (FCAEA), who described the reporters as "consummate professionals", said that while their release was "a big relief... the incident bodes ill for our work in Burundi."