The Export Price Index (won basis) fell to a 28-year low of 82.71 last month, down 4.2 percent in December 2014, fueling worries that "the fall could further undermine profitability of South Korean exporters," the Bank of Korea (BOK) said.
The index decreased 8.5 percent on-year in January.
The central bank said import prices also tumbled 7.3 percent in January from the previous month, largely due to a fall in oil prices.
The Import Price Index dropped to 80.25 last month, the lowest since November 2007. It plunged 19.2 percent on-year in January.