Criminologists have long been interested in predicting assaultive behavior and they share with correctional administrators an interest in finding ways to reduce the incidence of prison-based violence. Earlier studies emphasized the relationship of overcrowding or population density and increased prison violence. The data for this study, subjected to regression and time series analyses, revealed that the assault data curve followed a nonlinear path. Several of the significant correlates of inmate-initiated assault (young age, black-to-white ratio) were anticipated, whereas several others were not, e.g., population density, staff inexperience. This study's strong inverse correlation between population density and assaultive crimes suggests that overcrowding stimulates the system to engage in compensatory actions that serve to reduce the overall level of violence. Table, figure, note, references