Opposition supporters were chased by security forces in riot gear
More than 100 people were detained for public order offences after Wednesday's protests in Tehran, officials say.
The protests coincided with an official rally to mark 30 years since the storming of the US embassy during the 1979 Islamic revolution.
The 109 people were on the fringes of an opposition-organised demonstration when they were detained.
Security spokesman Azizollah Rajabzadeh said 62 are due to face trial while the others were released after questioning.
In recent months the opposition has used officially sanctioned demonstrations to come out in big numbers and publicise its own own messages.
Witnesses told the BBC the security forces had used tear gas and batons on Wednesday. The government defended the response, saying that the protests had been illegal.
Opposition supporters say the elections were rigged to ensure the re-election of President Mahmoud Ahmadinejad.
At least 30 protesters have been killed in clashes since the elections. Thousands have been arrested, and some 200 opposition activists remain behind bars. Three have been sentenced to death.
Meanwhile, the Danish government has said it is trying to make contact with Danish journalism student Niels Krogsgaard, who was held in Iran after covering the latest anti-government protests.
Iran has tightened reporting rules since protests flared in the days following a disputed presidential election in June.
A reporter for the French news agency AFP, Farhad Pouladi, was held on Wednesday but released on Saturday.
The semi-official Fars news agency had reported on Friday that he had been detained along a Canadian and a Japanese reporter for covering the protests without a permit.
On Saturday, Irna reported Tehran's general prosecutor had announced the release of one Canadian and two Germans.
There has been no confirmation so far whether this is the same Canadian.