Zambia officially charged former President Rupiah Banda for abuse of authority over a Nigerian oil deal, a government spokeswoman said on Monday.
Banda, who has been accused of misappropriating more than $11 million during his three years in office, was arrested and then later released on a bond, said Namukolo Kasumpa, a spokeswoman for the government's investigation team.
This month, Zambia stripped Banda of immunity from prosecution, a sign it was getting closer to bringing formal charges against him.
The former president was questioned for nearly three hours after his arrest, his lawyer Sakwiba Sikota said, adding that Banda had done nothing wrong.
Banda later appeared before supporters telling them to remain calm and that he would win his case in court.
The former president denies the charges and says he is "the victim of a witch-hunt".
He is due in court on Tuesday.
Banda was defeated in 2011 by rival Michael Sata, whose government has launched several high-profile corruption probes into deals struck by the former administration.