This study examines the lipid characteristics in king mackerel fillets after cooking and chill-reheating. Cooking using methods like shallow fat frying and grilling increased the total lipid content due to moisture loss. Cooking also altered the fatty acid composition and increased lipid oxidation. Reheating the cooked fillets after two days of chilling did not significantly further impact the lipid content or stability. The changes caused by cooking and reheating depended on the original lipid levels and cooking methods used.