The study of a carrion fauna from a forensic perspective provides insight into cadaveric succession during vertebrate decomposition and contributes to documentation of taphonomic processes. The insects associated with sea lion bones of 1290 ± 100 years BP found in Puerto Madryn (Argentina) were examined. The recorded species were: Cochliomyia macellaria and Fannia sp. (Diptera), Dermestes maculatus and Necrobia rufipes (Coleoptera), and Tineola cf. biselliella (Lepidoptera). The succession of insect species occurred at the end of spring or the beginning of summer, on carrion exposed to the open air for approximately 50 days. Decomposition was apparently interrupted by mass wasting that buried the carcasses.