Alexei Navalny, the opposition leader and anti-corruption blogger, was charged Thursday with fraud and money laundering.
Investigators accused Navalny and his younger brother, Oleg, of being involved in a scheme to cheat a mail transportation company out of 55 million rubles ($1.79 million).
If he is found guilty of fraud, Navalny could be jailed for up two years. He denies any wrongdoing and says the accusations are politically motivated.
The Navalny family said after the criminal investigation was first opened that the accusations were intended to persuade him to stop his opposition activities.
Reacting on his Twitter account, Navalny said his father has also been mentioned in the accusations leveled by the Investigative Committee.
Of his children, he said: "It's a good thing Dasha and Zakhar are underage."
Navalny, 36, already faces up to 10 years in jail if found guilty of earlier charges of theft from a state timber company.
He says those charges are part of a Kremlin campaign to discredit him and silence the opposition since Vladimir Putin returned to the presidency in May.
The cases against Navalny have drawn comparisons with the arrest of former oil tycoon Mikhail Khodorkovsky in 2003. He was sentenced to 13 years in jail on money-laundering and tax evasion charges after he fell out of favor with Putin.
A court ruled on Thursday that Khodorkovsky could leave jail two years early in 2014.