The head of the European Union 2005 election observers in Ethiopia has said she is "appalled" at the life sentences given to 30 opposition leaders.
The opposition blames the violence on the security forces
Ana Gomes told the BBC the sentences were "farcical" and "inhumane" and urged the EU to seek their release.
Another eight people were given shorter jail terms, while five were tried in absentia for their role in violent protests at alleged poll-rigging.
Ethiopia's information minister hinted that the 38 could soon be freed.
Bereket Simon told the BBC's Focus on Africa programme that the government was looking into their apology and request for a pardon
"The prisoners have admitted... trying to overthrow the government by the use of force and have asked for clemency."
He said that now that the legal process had ended, a new political process would start.
15-18 years: 6
1-3 years: 2 journalists
Many Ethiopians expect the 38 to be freed soon by the government.
Their relatives say the detainees have signed a document which could pave the way for their release.
The prosecution had demanded the death penalty for them all.
Ms Gomes told the BBC's Focus on Africa programme that she thought life in prison was just as bad as the death penalty.
"[Their] only crime was to express their opinions freely in elections, which were supposed to be democratic," she said.
High court judge Adil Ahmed also barred the 30 Coalition for Unity and Democracy (CUD) leaders from voting or standing for election.
The opposition leaders say the charges were political
"The accused have committed serious crimes, which caused the death of civilians and security forces and attempted to overthrow the government," he said.
"The accused have also failed to present to the court mitigating evidences for the charges brought against them."
But he said they did not deserve the death penalty.
Before the sentences, the US had warned that any judgement should promote reconciliation between the government and the opposition.
The BBC's Elizabeth Blunt in Addis Ababa says the trial has been closely watched in the city, a CUD stronghold.
She says that the entire front row of seats in the court was taken up by diplomats and a simultaneous English translation was provided.
Five of the 38, including CUD leader Hailu Shawel, were convicted of inciting, organising and leading armed rebellion.
Among the 38 are the entire CUD leadership, several of the capital's elected MPs and city councillors, including Berhanu Negga, mayor-elect of Addis Ababa.
Hundreds of thousands took part in demonstrations complaining of fraud and rigging in the elections won by Prime Minister Meles' party.
Some 193 people were killed in protests at alleged vote-rigging.
Most of the dead were protesters, killed by security forces.
An independent inquiry carried out by an Ethiopian judge concluded that the police had used excessive force.
He went on to accuse them of carrying out a massacre. The judge later fled Ethiopia, saying he had been put under pressure to change his findings and had received death threats.
The government points out that it introduced multiparty elections to Ethiopia after years of military rule.
In the elections, the opposition made huge gains but says it was cheated out of victory.
Three months ago, a judge threw out controversial charges of attempted genocide and treason against 111 people, including those sentenced on Monday, over the election protests.
The violence and the charges of election fraud have tarnished Mr Meles' image as a favourite of Western donors and one of a new wave of reforming African leaders.
Some donors have reduced aid over the case.