The producer price index stood 7.3% higher in October than the same month a year ago, according to the Bank of Korea (BoK), after a revised 7.9% rise in September.
The rise was the slowest since June 2021. Producer inflation had hit a near 14-year high of 10.0% in June.
On a monthly basis, however, the index rose 0.5%, picking up from a revised 0.1% in September and the fastest in four months.
The monthly rise was led by utility prices for electricity, gas, water supply and waste, which jumped 8.1%.
South Korea's central bank is expected to scale back its tightening pace later on Thursday and hike rates by a modest 25 basis points amid signs of slowing domestic growth, despite high inflation and an aggressive U.S. Federal Reserve, a Reuters poll found.
(Reporting by Jihoon Lee; Editing by Kim Coghill)