Of 28,867 people who cast ballots, 24,531 or 84.97 percent expressed objections to the construction plan - many of them appeared to be mindful of Japan's Fukushima disaster three years ago. Only 4,164 people or 14.4 percent voted for it.
A group of Samcheok citizens organized and administered the vote, after the local election commission rejected their request to hold a referendum on building a nuclear power plant in the region.
Voter turnout stood at 67.9 percent - of 42,488 registered voters, 28,867 cast ballots.
After the vote counting, Samcheok Mayor Kim Yang-ho urged the central administration to accept the residents' opinion.
Before being elected as mayor in June, Kim pledged to scrap the plan to build the plant. His predecessor Kim Dae-su was in favor of it.
The central government, however, said it will push ahead with the plan, saying that the vote has "no legal validity."