The charges cover a range of alleged misdeeds, including conspiracy and money laundering.
A federal judge has issued a summons for Nagin to appear in court on the charges.
Nagin has re-tweeted a quote on his Twitter account today. It reads, "You are closest to your victory when you face the greatest opposition." The original tweet came from @JoelOsteen.
Mayor Mitch Landrieu said in a news release, "This is a sad day for the city of New Orleans...Today’s indictment of former Mayor Ray Nagin alleges serious violations of the public’s trust. Public corruption cannot and will not be tolerated.”
Former associates and colleagues of Nagin are apparently set to testify that the former mayor traded the influence for cash and other bribes in exchange for allegedly steering millions of dollars in city business to certain individuals.
Nagin has apparently been the subject of an ongoing federal investigation for some time.
Greg Meffert, who modernized the city's website and other information technology, pleaded guilty to accepting bribes and kickbacks from Mark St. Pierre, a city contractor. Nagin went on lavish tropical vacations with Meffert which the former mayor says he thought was paid for by his employee, but Meffert says that money actually came from St. Pierre.
In June, another former city supplier, Frank Fradella, pleaded guilty to bribing an unnamed New Orleans official $50,000 and giving that official free granite for the official's family's business. Legal experts say that "unnamed official" is almost certainly Ray Nagin.
More recently, local businessman Rodney Williams agreed to cooperate with investigators after allegedly paying off an "unnamed city official" payoffs in exchange for steering city work to Williams between 2007 and 2010.
In the case against Fradella, prosecutors say he provided truckloads of free granite to the unidentified official. The company run by Nagin's two sons obtained a contract to install granite countertops for local Home Depot stores after Hurricane Katrina struck in 2005.
A lawyer for Nagin's two sons, Jeremy and Jarin, told a local newspaper and television stations in October that his clients were summoned to appear before the grand jury investigating their father.
Fradella, who is scheduled to be sentenced in March, was CEO of Home Solutions of America Inc., a publicly traded disaster reconstruction firm.