Background: Childhood sexual and physical abuse has been related to subsequent offending behaviour in non-disabled individuals as well as people with intellectual disabilities, but there is a dearth of research examining the link between these two characteristics and psychological, behavioural and psychiatric symptoms amongst sex offenders with intellectual disabilities. The aim of this study was to examine the relationship between childhood abuse, history of psychological and psychiatric symptoms, and patterns of violence in later offending. Methods: Twenty sex offenders with intellectual disabilities were compared with 20 non-disabled sex offenders. The Kaufman Brief Intelligence Test, the Vineland Adaptive Behavior Scales, and a structured clinical interview were administered to participants. Results: Offenders with ID were more likely to report that they had been the victim of physical abuse during childhood; aggressive behaviour during adulthood was related to a history of having been the victim of childhood physical abuse, or exposure to family violence. Participants in the ID group were more likely to be diagnosed with depression, post-traumatic stress disorder and aggressive behaviour. A history of childhood exposure to violence was related to the development of later symptoms, for both ID and non-disabled offenders. Perpetrators with ID who had been physically abused during their developmental years were significantly more likely to threaten or use violence during the offence. Conclusions: The study suggests that childhood abuse may be related to severity of the crime, and to the development of later psychological and psychiatric symptoms. Longitudinal research in this area and a larger sample size are needed to clarify and extend the present findings.