The case is the most prominent test so far of the country's 1997 law on religion, which is designed to curb the activities of foreign religious organizations seeking new members in Russia.
Prosecutors brought charges under an article seeking to outlaw dangerous cults. The indictment accuses the Jehovah's Witnesses of inciting religious discord, splitting families, promoting suicide, and denying medical care to the critically ill.
Human rights advocates have warned that, although Russia's constitution officially protects freedom of worship, a ruling against the Witnesses could be used to outlaw any religious group that falls out of favor with authorities.
"This is a major test case," said Diederik Lohman, director of the Moscow office of Human Rights Watch. "If they win this case, they can easily use it as a precedent to close down groups throughout Russia."
The ruling in the trial, being held in a small, stuffy local district courtroom in northern Moscow, will technically apply only to that district of the city. But both sides say its impact will be felt throughout Russia.
"The central issue is whether the government can classify any religious group they want to close down as a cult," said Lawrence Uzzell, Moscow director of the Oxford-based Keston Institute, which monitors religious freedoms in former Communist countries.
The central accusation against the Witnesses is that they "foment religious strife" by claiming to be "the only true religion." That is an assertion made by nearly every faith, Uzzell said.
"Any religion that claims to be in possession of a divine revelation -- as all major world religions do -- could be outlawed if they should fall out of favor with the authorities," he said.
Prosecutors have said that they hope to call dozens of family members of Jehovah's Witnesses to testify about the group's practices.
"We believe they are violating Russia's civil laws," the lead prosecutor, Natalya Adamova, said. "When you propagandize against other religions, you should stay within certain boundaries and not insult the other faiths. We think that's what they are doing."
Prosecutors cite literature that refers to people outside the Jehovah's Witnesses as "adherents to the world of Satan." They also cite the Witnesses' prohibition of blood transfusions as evidence for the charges of promoting suicide and denying medical care.
Critics have noted that the charges are based on general assertions of the group's beliefs and practices, not specific cases of alleged wrongdoing.
"What they are trying to do is close them down purely on the basis of what they write and what they say," Uzzell said. "That's discriminatory. It's treating some religious ideas more favorably than other ideas."
Russia's religion law has its roots in Soviet-era repression of all faiths. Certain groups, including the Russian Orthodox Church, were allowed to worship in a restricted manner, but they were forced to register with the authorities and could not actively recruit new members, even their own children.
The religion law, promoted by the Orthodox Church and signed by Boris N. Yeltsin in September 1997, recognizes only four faiths as "traditional" in Russia: Orthodoxy, Islam, Judaism and Buddhism.
The law requires groups perceived to be "foreign" to demonstrate a continuous 15-year presence in Russia before they are permitted to worship publicly.
Jehovah's Witnesses, unlike many religious groups, were active in Russia before the Bolshevik Revolution. Several thousand members were exiled to Siberia during the Stalinist era. The group has been expanding rapidly in recent years, and claims 100,000 committed members.