Mike Sorrentino -- The Situation Indicted For Tax Fraud

11:48 A.M. PDT -- Mike and Marc Sorrentino just walked out of court ... both were released on $250K bond. Their lawyers say the brothers are not guilty. They'll be arraigned Oct. 6th.

The Situation has just been charged with the crime of tax evasion in New Jersey ... TMZ has learned.

According to the indictment ... obtained by TMZ ... the U.S. Attorney in NJ claims Mike "The Situation" Sorrentino did not pay his full tax bill on $8.9 million in earnings. In fact, prosecutors claim he intentionally filed fraudulent returns in order to make it appear he was square with the IRS.

The Situation's brother, Marc, was also charged with conspiracy to commit tax fraud.

Both the Situation and his brother are expected to surrender to federal authorities Wednesday. Sitch is facing a maximum sentence of TWELVE years in the federal pen.

He posted this on Instagram 30 minutes ago: "to be old and wise you must first be young and dumb."