Stomach contents were analysed for 292 medium size (<45 cm mantle length) jumbo squid, Dosidicus gigas, caught in the Gulf of California and adjacent waters in 1998–2000. Diet varied by location and was dominated, in different places, by mesopelagic fishes as Benthosema panamense, Triphoturus mexicanus, and Vinciguerria lucetia. This general pattern of feeding on myctophids coincided with that for large size jumbo squid in 1995–1997. Pteropods, micronektonic squid, megalopae, and euphausiids were second in importance and some were consumed in larger amounts than in previous years. It is difficult to discern whether these differences in diet were due to a smaller squid size or to a change in the pelagic environment after the 1997–98 El Niño event.