The National Election Commission announced the official results of the April 27 by-elections. In the Seongnam Bundang-B district, Sohn Hak-kyu, leader of the main opposition Democratic Party (DP), won the National Assembly seat. Kim Seon-dong of the Democratic Labor Party (DLP) won the seat in Suncheon-si, while Kim Tae-ho of the ruling Grand National Party (GNP) won in Gimhae-B constituency. In the election for gubernatorial post of Gangwon Province, Choi Moon-soon of the DP got elected. 

Of thirty-eight seats in the by-elections, the GNP won seventeen seats, compared to twelve seats won by the DP. Four seats went to the Liberty Forward Party, while the DLP won four seats, and one was won by an independent.

The NEC said that the average turnout marked 39.4 percent, a 4.9 percent increase from 34.5 percent of the by-elections in the first half of 2009. In particular, in the most closely-watched contest, Bundang-B constituency, turnout marked a 3.9 percent increase from the 18^th National Assembly elections.

Of all the districts, Hwasun-gun-2-district witnessed the highest turnout rate of 66.1 percent, compared to the lowest turnout rate of 9.5 percent recorded in Gangnam-gu-C-district.