Salem oncologist Bud Pierce will be the Republican Party's challenger to Gov. Kate Brown in November.
Pierce, a political novice, led with 48 percent of the vote, according to initial returns.
Allen Alley, former head of the Oregon Republican Party and a tech executive, trailed Pierce with 30 percent of the vote.
Oregon voters haven’t elected a Republican to the state’s top office in 34 years. But Pierce says he believes his private-sector resume and practical approach will prove a convincing message against Brown, the former secretary of state who became governor when John Kitzhaber resigned last year.
Brown won her own primary easily Tuesday night.