The fat in 220 samples from 35 food types has been analyzed for component fatty acids by gas liquid chromatography on a 15‐m capillary column coated with SP‐2340. The methodology permitted the determination of trans‐octadecenoic fatty acids in the food samples. For food types in which the majority of samples containedtrans fatty acids, the range (weight percent of methyl esters) of this class of acids arranged by fat content of the food types was: high fat levels (>70% fat) — animal and dairy fats, 0.3–6.6%, stick margarines, 15.9–31.0%, tub margarines, 6.8–17.6%, and vegetable shortenings, 8.7–35.4%; moderately high fat levels (40–70% fat) —diet margarines, 11.3–13.3%; moderate fat levels (10–40% fat) — breading mixes and fried crusts, 8.1–32.7%, cakes, candies and frostings, 3.2–33.2%, cream substitutes, 0.4–11.5%, cookies, 2.5–34.2%, crackers, 1.9–29.0%, pastries and pastry crusts, 0.6–31.2%, corn and mixed grain snack chips, 0.4–30.4%; low fat levels (<10% fat) ‐ breads and rolls, 0.2–23.6%, pretzels, 10.8–29.2%, and puddings, 28.4‐35.1%. The majority of samples in the following food types did not containtrans fatty acids, except in cases where the label indicated partial hydrogenation of the oil: mayonnaises and salad dressings, salad and cooking oils and potato chips. For samples in these three food types which containedtrans fatty acids, the range was 0.2‐23.2%. None of the peanut butters or pizza crusts analyzed containedtrans fatty acids.