Although there is evidence that consumption of trans fat has declined in the United States, limited documentation exists on current levels of industrial trans fat in foods. We estimated the prevalence of partially hydrogenated oils in 4,340 top-selling US packaged foods. Nine percent of products in the sample contained partially hydrogenated oils; 84% of these products listed "0 grams" of trans fat per serving, potentially leading consumers to underestimate their trans fat consumption. Government efforts to eliminate partially hydrogenated oils from packaged foods will substantially reduce exposure to this known cardiovascular disease risk factor.