Marynich spent nearly two years in custody. Under his original sentence, in December 2004, he was due to serve five years in prison. His term was later reduced to 2.5 years. Earlier this week, a court in Minsk approved a request for his early release.
Marynich was jailed in a case widely condemned as fabricated and politically motivated. He was imprisoned for allegedly stealing computers from the U.S. Embassy in Minsk, even though the embassy had not reported any such theft.
Marynich, a former minister and ambassador, had challenged authoritarian leader Alyaksandr Lukashenka for the presidency in the 2001 elections.
(Belapan, Charter 97, dpa, AP)