Background It is unclear whether adult offenders with a history of attention deficit hyperactivity disorder (ADHD) are more likely to re-offend and, if so, in any specific offences. Aim To examine correlates of childhood ADHD symptoms among prisoners. Methods A randomly selected sample of 1,179 participants from the adult sentenced population of Puerto Rico (USA) reported their history of violent and non-violent offences, age of first arrest and reoffending. Participants completed retrospective measures of ADHD and a diagnostic interview for substance use disorders. Results Self-reported ADHD was associated with age of first arrest, a number of violent and non-violent offences and re-offending. The association with any non-violent offending was explained statistically by substance use disorders and other psychosocial covariates. ADHD was independently associated with being under 15 years of age at first arrest, and with re-offending. Conclusions Although some associations between ADHD and offending may be accounted for by comorbidity with substance use disorders, early onset of offending and repeated violent offending appear to be directly related to ADHD. Criminal justice policies should, therefore, incorporate ADHD screening accompanied by appropriate rehabilitation programmes when such neurodevelopmental disorder is identified.