Analysis of the stomach contents of 204 blue martin (Makaira mazara) caught by the sport-fishing fleet of Cabo San Lucas in the southern Gulf of California is presented. The specimens sampled were caught during the summer and fall of 1987, 1988, and 1989 when the sea is warm (28-30 degrees C). Blue martin were found to feed on 35 prey species, 3 of which represented 90% of the total stomach contents by frequency of occurrence. The main prey were epipelagic organisms from the oceanic zone and demersal fishes from the neritic zone. The most important prey were bullet mackerel Auxis spp., young finescale triggerfish Balistes polylepis, and the giant squid Dosidicus gigas. (C) 1999 Elsevier Science B.V. All rights reserved.