Reconstructions of Eurasian Neanderthal diets based on stable nitrogen isotope ratios (δ 15 N) typically place hominins at the top of the food web, together with, or above, hypercarnivores, such as lions and wolves. We suggest that these high δ 15 N values may, in part, reflect the regular consumption of 15 N-enriched fly larvae (maggots) occurring in stored animal foods. The ethnohistoric record contains countless examples of Indigenous peoples routinely consuming putrefied animal foods with maggots. Here, we report the results of δ 15 N bulk analyses of fly larvae of three families (Diptera: Brachycera: Calliphoridae, Piophilidae, and Stratiomyidae) collected from putrefying carcasses. Putrefaction led to modest changes in the initial muscle tissue δ 15 N values that ranged from −0.6 to 7.7‰. Much greater δ 15 N values ranging from 5.4 to 43.2‰ were observed in the fly larvae associated with putrefaction. We suggest that frequent consumption of animal foods laced with maggots should be considered as a contributor to the high δ 15 N values observed in Late Pleistocene hominins.