13 July 2012 Last updated at 12:17 GMT
Eskinder Nega and 23 others were found guilty last month.
They were accused of links with US-based opposition group Ginbot Seven, which Ethiopia considers a terrorist organisation.
Opposition activist Andualem Arage was given a life sentence by the court in the capital, Addis Ababa.
In May, Eskinder was awarded the prestigious Pen America’s Freedom to Write annual prize for his work.
Human rights groups have criticised Ethiopia’s anti-terrorism legislation for being too far-reaching.
“The court has given due considerations to the charges and the sentences are appropriate,” Reuters news agency quotes Judge Endeshaw Adane as saying.
Eskinder and Andualem, a member of the opposition Unity for Democracy and Justice party, were in court on Friday to hear their sentence – 16 members of the group found guilty in June are in exile, AFP news agency reports.
The two men waved to family members as they walked into the courtroom which was filled with friends and family of the activists, as well as journalists and diplomats, the agency says.
Eskinder was arrested last September after publishing an article questioning arrests under the anti-terrorism legislation, especially that of well-known Ethiopian actor and government critic Debebe Eshetu.
In 1993 Eskinder opened his first newspaper and has been detained at least seven times by the government of Prime Minister Meles Zenawi.
Right group Amnesty International said the trial fell short of international standards.
“The imprisonment… is emblematic of the Ethiopian government’s determination to gag any dissenting voice in the country,” Amnesty’s Ethiopia researcher Claire Beston said in a statement.
“The Ethiopian government is treating calls for peaceful protest as a terrorist act and is outlawing the legitimate activity of journalists and opposition members.”
An Ethiopian guard working for the UN was jailed for seven years for communicating with the banned Ogaden National Liberation Front (ONLF) in June.
In December, two Swedish journalists were sentenced to 11 years in prison for supporting the ONLF.
Both the ONLF, which has been fighting for greater independence in the Ogaden area that borders Somalia, and Ginbot Seven, have been designated as terrorist groups by the Ethiopian parliament.