The application of modern methodological taphonomic approaches to Pleistocene faunal assemblages that were excavated and interpreted before taphonomic analyses became common are critical to verifying whether the original interpretations are valid. Even though taphonomic research is common in North America, Africa, and Europe, few such studies of faunal collections have been carried out in East Asia. In this regard, taphonomic analysis of the faunal assemblage from Hanaizumi, Japan serves as an excellent case study because few taphonomic re-analyses of previously excavated Pleistocene assemblages have been performed in Japan. Hanaizumi was excavated in the 1950s and the original behavioral interpretation was that hunter-gatherers were responsible for the accumulation of the faunal assemblage, which is dominated by bison (Bison priscus). The taphonomic analysis presented here indicates that evidence of human modification is present on the bones. However, results suggest that even though hunter-gatherers may have had primary access to many of the bison in the assemblage, Hanaizumi was probably not a kill site or a hunter-gatherer home base as was originally proposed. Rather, the acquisition of bison may have taken place further up river and Hanaizumi is the locality to which the already processed carcasses were transported via fluvial movement. Accordingly, it is difficult to use the Hanaizumi faunal dataset to address current paleoanthropological debates. Future fieldwork at the site may indicate that hunter-gatherers played a more significant role in the formation of the bison bone assemblage. For now, Hanaizumi is best considered an allochthonous paleontological collection that has assisted in paleoenvironmental reconstructions of Late Pleistocene Japan.