The opponents are charged with coordinating and "inciting mass disorder" that led to violence between demonstrators and security forces.
The list also includes a swathe of the country's media elite, who have been arrested since protests erupted following President Aleksander Lukashenko victory for a fourth term in office on Sunday.
More than 700 people, including 25 journalists, were arrested during Sunday's protests.
Pavel Sapelko, lawyer of one of the candidates, said his client, Andrei Sannikov, was beaten so badly in the election aftermath that he suspects he has a broken leg. He was even refused an X-ray, the lawyer told AP.
He said Sannikov received the most votes among the opposition candidates -- 2.4 percent, compared with winner Alexander Lukashenko's 79.6 percent.
Meanwhile, lawyer Tamara Sidorenko said her client, Vladimir Neklyayev, another prominent challenger, was also beaten as he tried to lead a column of supporters to the protest in central Minsk and was taken to a hospital.
If they are found guilty, they could face up to 15 years in jail, Ales Belyatsky of Belarusian human rights organization Vesna said Wednesday.