The stomachs of 6,933 Spanish mackerel were examined. The mackerel were caught by hook and line, seines, and gill nets between August 1977 and November 1981 from continental shelf waters off Texas, Louisiana, northwest Florida, East central Florida, and North and South Carolina. Differences in stomach contents by area, gear, size of predator, year, and season were studied. Data are presented as percentage volume and percentage frequency of occurrence. About 64% of the stomachs were empty. Among stomachs with food the percentage volume of fish, the dominant food category, ranged from 95.6% in Texas to 99.1% in east central Florida. while the percentage frequency of occurrence of fish ranged from 94.3% in Louisiana to 97.6% in North and South Carolina. Shrimp or squid, depending on the area, was the second most important prey. Eleven families and 24 species of fishes were represented in the diet, with Engraulidae being the most prevalent group of fish prey. Small Spanish mackerel ate mainly anchovies. Larger Spanish mackerel consumed increasingly larger amounts of other fishes, crustaceans, and squid. The stomachs of net-caught Spanish mackerel contained higher percentages of digested fish remains and were more frequently empty than stomachs from hook-and-line caught Spanish mackerel. Clupeidae and Carangidae were represented more in stomachs of Spanish mackerel caught by hook and line than in those caught by nets.