Self-injurious behavior (SIB) is inherently problematic because it can lead to injuries, including those that are quite severe and may result in loss of function or permanent disfigurement. The current study replicated and extended Rooker et al. (2018) by classifying the physical characteristics of injuries across groups of individuals with automatically maintained SIB (ASIB Subtypes 2 and 3) and socially maintained SIB. Individuals with Subtype 2 ASIB had the most frequent and severe injuries. Further, an inverse relation was found between the level of differentiation in the functional analysis and the number of injuries across groups. Studying the response products of SIB (the injuries) documents the risks associated with SIB, justifies the need for research and the intensive intervention, and advances knowledge of SIB. Additional research is needed to replicate these findings, and determine the variables that produce different characteristics of injury secondary to SIB.