Palm oil and soybean oil are the 2 most widely used cooking oils in the world. Palm oil is consumed mainly in developing countries, where morbidity and mortality due to cardiovascular disease (CVD) are on the rise. Although claims about adverse or protective effects of these oils are commonly made, there are no epidemiologic studies assessing the association between these oils and cardiovascular disease endpoints. We examined whether consumption of palm oil relative to soybean oil and other unsaturated oils (predominantly sunflower) is associated with myocardial infarction (MI) in Costa Rica. The cases (n = 2111) were survivors of a first acute MI and were matched to randomly selected population controls (n = 2111). Dietary intake was assessed with a validated semiquantitative FFQ. Adipose tissue profiles of essential fatty acids were assessed to validate cooking oil intake and found to be consistent with self-reported major oils used for cooking. The data were analyzed using conditional logistic regression. Palm oil users were more likely to have an MI than users of soybean oil [odds ratio (OR) = 1.33; 95% CI: 1.08-1.63] or other cooking oils (OR = 1.23; CI: 0.99-1.52), but they did not differ from users of soybean oil with a high trans-fatty acid content (OR = 1.14; CI: 0.84-1.56). These data suggest that as currently used in Costa Rica, and most likely in many other developing countries, the replacement of palm oil with a polyunsaturated nonhydrogenated vegetable oil would reduce the risk of MI.