The Sorrentinos have both been charged with one count of conspiracy to defraud the United States, according to paperwork obtained by ABC News last month.
Mike Sorrentino, 32, was also charged with two counts of filing false tax returns for 2010-2012, while his older brother was charged with three counts of the same.
Mike Sorrentino also is accused of failing to file a tax return for 2011, when authorities claimed he earned nearly $2 million.
Both brothers face a maximum of five years in prison if convicted.
"According to the indictment, Michael and Marc Sorrentino filed false tax returns that incorrectly reported millions made from promotions and appearances," U.S. Attorney Paul J. Fishman told ABC station WABC in New York City at the time. "The brothers allegedly also claimed costly clothes and cars as business expenses and funneled company money into personal accounts. The law is absolutely clear: Telling the truth to the IRS is not optional."
Mike Sorrentino did not comment outside the courtroom after today's proceedings.