This article discusses why OECD countries should simplify their rules of origin (RoO) in preferential trade agreements (PTAs) to help developing countries trade more easily. Current RoO systems are complicated and costly, mainly benefiting the Northern partner. The rules often force Southern countries to buy more expensive materials from the Northern countries. The research shows that the strict RoO are not necessary to prevent trade cheating and mostly benefit special interest groups. The authors suggest that reforms are needed to make trade rules fairer and more helpful for developing nations.