South Korea's antitrust regulator fined Qualcomm the largest ever fine levied in the country - $854 million - for abusing its dominant market position and forcing handset makers to pay for unnecessary patents.
The Korea Fair Trade Commission also said Qualcomm restricted competition by refusing or limiting licensing to rivals, like Intel and Samsung.
The regulator ordered Qualcom to negotiate patent licensing with other chipmakers, and renegotiate chip supply agreements with handset makers.
Qualcomm said it will appeal the decision.
The fine is the latest in a series of antitrust rulings and investigations faced by Qualcomm from regulators across the globe. On the list - China, European Union, Taiwan, and the United States.