This article examines prison misconduct of inmates who tested as mentally retarded, borderline intellectual functioning, and intellectually normal. The sample is drawn from a cohort of inmates released from the New York State correctional system. Misconduct is measured by examining official documents and is divided into two types: non‐violent and violent incidents. Analysis of variance suggests that the mentally retarded had significantly higher reported mean annual rates of involvement in both non‐violent and violent incidents. However, results of multiple regression analysis indicate that, when controlling for the effects of several social and criminal history factors, IQ score has a significant effect on the violent, but not the non‐violent, incident rate. Age and employment status at time of arrest have the strongest influence on an inmate’s disciplinary incident rate, while IQ score has the smallest influence of the variables examined in this study.