Federal court records show that Paul Winfield was indicted Tuesday. He had already been charged in a criminal complaint in the case. He will be arraigned March 28 in Jackson.
The FBI arrested Winfield on Feb. 20. He has pleaded not guilty and was released on a $10,000 bond.
The 39-year-old Democrat is accused of seeking $10,000 in exchange for a city contract.
Prosecutors say an informant paid the first-term mayor $5,000 in cash in July and agreed to pay more when the contract was awarded.
In August, Winfield asked for more money, saying he needed to pay taxes. Court records say they met in the parking lot of a McDonald's in Natchez, where the informant gave Winfield another $2,000.