Cold tolerance of striped bass Morone saxatilis, white bass M. chrysops, palmetto bass (female striped bass × male white bass), and sunshine bass (female white bass × male striped bass) were compared under controlled laboratory conditions. Two groups of each taxon were acclimated at 20°C in a recirculating-water system housed in an environmental chamber and were fed either a natural or prepared diet for 84 d. The fatty acid composition of the natural diet was 13% more unsaturated than that of the prepared diet. Fish fed the natural diet subsequently had unsaturated:saturated fatty acid ratios 10–25% higher than fish fed the prepared diet. After being subjected to identical simulated cold fronts (10°C drop in surface water temperature, as if the fish were confined in cages or pens), all groups of fish fed the prepared diet suffered high mortality (50–90%) whereas there was zero mortality among the groups receiving the natural diet. White bass and sunshine bass fed the prepared diet had higher survival rates (50% and 40%, respectively) compared with their striped bass and palmetto bass counterparts (10% and 20%, respectively). The lower incipient lethal temperature was higher for fish fed the prepared diet (5.9, 4.8, 2.5, and 1.9°C for striped bass, palmetto bass, sunshine bass and white bass, respectively) than for those fed the natural diet (near 0.0°C, but 1.8°C for sunshine bass). Both studies reflect a maternal affect on cold tolerance, with white bass being most tolerant. We demonstrated that diet-induced muscle fatty acid composition directly affects cold tolerance of striped bass, white bass, and their hybrids.