READ MOREThe net terms-of-trade index for goods stood at 96.26 in April, down 5.2 percent from a year earlier, according to the Bank of Korea (BOK). It was the lowest since January 2015.
From a month ago, the index declined 0.9 percent last month, keeping a downward trend for the third consecutive month.
The index refers to an amount of goods that can be imported with an export unit proceed.
The worsened trade terms stemmed from higher crude oil prices. Dubai crude, South Korea's benchmark, averaged 68.27 U.S. dollars per barrel in April from 62.74 dollars in March.
In terms of volume, imports gained 5.6 percent on strong demand for mining products, including crude oil, which jumped 11.5 percent last month.
The import value index surged 15.7 percent on higher crude oil prices. ■