The benchmark Korea Composite Stock Price Index fell 11.87 points, or 0.48 percent, to close at 2,480.63. The drop came after the main index rose 0.8 percent over the past four sessions.
Trade volume was moderate at 638.07 million shares worth 7.05 trillion won ($6.3 billion), with decliners outnumbering advancers 454 to 358.
Foreigners and individuals sold a combined 61.7 billion won worth of stocks, offsetting 61.6 billion won worth of stocks bought by institutions.
Tech stocks led the losses, with market bellwether Samsung Electronics Co. falling 2.78 percent to 2,620,000 won and No. 2 chipmaker SK hynix Inc. declining 3.67 percent to 78,700 won.
In contrast, top carmaker Hyundai Motor Co. jumped 7.41 percent to 159,500 won on hopes the worst may be over in China sales. Its net profit fell 16 percent on-year to 939.2 billion won in the third quarter due to weak demand in the world`s largest automobile market.