At a rally in Chita, where Khodorkovsky is serving his eight-year sentence for tax evasion and fraud while awaiting trial on a new set of charges, supporters plan to hand out birthday cards for people to send to the former oil tycoon, and to offer refreshments.
Participants then plan to move closer to the detention center, where they will unfold a banner reading "Happy birthday, Misha!" and set off fireworks.
An organizer of similar events near the prison last year was fined for public order offenses.
In Tomsk, over 2,700 km (1,670 miles) southeast of Chita, the local branch of the opposition party Union of Right Forces (SPS) will hold a roundtable on economic issues timed to coincide with the businessman's birthday, an SPS member said Wednesday.
"Tomorrow the Committee on Public Support for Khodorkovsky is organizing a picket ... to prevent people from forgetting that an innocent man is in prison," Alexei Toropov said. "A new president has been elected, but he (Khodorkovsky) is still in prison,"
Khodorkovsky and fellow Yukos executive Platon Lebedev, who is in prison on similar charges, have maintained their innocence. Khodorkovsky said his imprisonment was a direct result of his support for Russia's tiny pro-Western opposition.
Toropov said Khodorkovsky was proof that much touted cuts in a tax burden and measures to curb red tape in Russia were empty talk.
"There has been a lot of talk about relaxing the tax burden and removing administrative barriers in the country. However, business, including big business, has not witnessed those changes. And Mikhail Borisovich [Khodorkovsky] is proof of that," the opposition activist said.
