The benchmark Korea Composite Stock Price Index dropped 9.1 points, or 0.38 percent, to close at 2,363.19.
Trade volume was a moderate 256 million shares worth 5.12 trillion won ($4.54 billion), with losers outnumbering gainers 442 to 329.
The local stock market opened higher as market sentiment was boosted by overnight gains on Wall Street but pared earlier gains as foreigners continued to offload more shares than they bought.
"The local stock market recovered most of its losses seen in the past sessions," said Lee Kyong-min, an analyst at Daishin Securities. "But ahead of key economic data from the US and a crucial policy meeting of the European Central Bank, many investors took to the sidelines."
Foreign investors sold a net 113 billion won, while retail investors bought a combined 134 billion won.
Market heavyweights traded mixed, with top cap Samsung Electronics rising 0.2 percent to end at 2,316,000 won.
SK hynix, a major chipmaker, advanced 0.15 percent to 68,600 won.
Shares of Hyundai Motor, South Korea's No. 1 automaker, backtracked 1.75 percent to end at 140,500 won on concerns over a protracted slump in China.
Kia Motors, the No. 2 automaker, suffered a 3.54 percent drop to end at 35,450 won after it was ordered by a local court to retroactively pay some 400 billion won to employees. The court ruled that regular bonuses should be included in the "ordinary wage" used as the basis for calculating overtime, severance and other payments.
Naver, the operator of the country's top Internet portal, shed 2.45 percent to end at 755,000 won.
Lotte Shopping, a retail giant, dropped 0.96 percent to end at 257,000 won on news that the group will inject another $300 million into its hypermarket chain in China, which is bearing the brunt of Beijing's apparent economic retaliation over Seoul's deployment of a US missile defense system.
Oil refiners were among gainers. SK Innovation, the No. 1 oil firm in the country, climbed 1.34 percent to end at 188,500 won.
The local currency closed at 1,127.80 won against the US dollar, down 3.6 won from the previous session's close.
Bond prices, which move inversely to yields, ended mixed. The yield on three-year Treasurys fell 0.5 basis point to 1.747 percent and the return on the benchmark five-year government bonds rose 1 basis point to 1.968 percent. (Yonhap)