Tibilov received 54.1 percent of votes, the republic's election commission said. His opponent, human rights ombudsman David Sanakoyev, received 42.6 percent.
The declared president-elect said he would work to unite the republic's people.
"Our people are wise, politically mature and, according to preliminary data, I am president-elect, for which I'm thankful to our citizens. The president must not alienate the people. I will work to unite and rally society," Tibilov said late Sunday, RIA-Novosti reported.
In the first round of the election held late last month, Tibilov garnered 42.5 percent of votes and Sanakoyev barely beat out the South Ossetian Ambassador to Russia Dmitry Medoyev for second place, with 24.6 percent of votes for Sanakoyev versus 23.8 percent for Medoyev. Local Communist Party leader Stanislav Kochiyev also participated.
A presidential vote was held in South Ossetia in November of last year, but the results were declared invalid by the republic's Supreme Court on grounds of vote fraud. In that election, opposition leader Alla Dzhioyeva appeared to have defeated Russia's favored candidate, Anatoly Bibilov.
