--- - |2+ Abstract Background Aggression replacement training (ART) is a widely used cognitive behavioural intervention for reducing aggression‐related recidivism among criminal offenders. Its effectiveness in reducing offending, however, remains uncertain. Aim To examine the effect of ART on adult offenders' criminal recidivism rates. Method We compared 1,124 convicted adult offenders who began ART in the Swedish Prison and Probation Services 2003–2009 with 3,372 offenders in the system at the same time who did not participate in ART. Linkage with nationwide, longitudinal registries allowed extensive propensity score‐matched controlling for baseline differences (e.g. sociodemographics, criminal history, psychiatric morbidity, and substance misuse) between groups. Results Intent‐to‐treat analyses suggested similar 1‐year general reconviction rates (according to the National Crime Register) between the two groups (ART participants 50% [n = 465]: comparison participants 51% [n = 1,492]; hazard ratio [HR] = 0.97, 95% CI [0.88, 1.07]) and similar one‐year violent recidivism (ART participants 19% [n = 174]: comparison participants 18% [n = 547]; HR = 1.02, 95% CI [0.89, 1.17]). For ART completers, findings suggested a marginal decrease in reconvictions for any recidivism, but not for violent recidivism specifically. Sensitivity analyses yielded similar results. Conclusions and implications Our findings add to the emerging literature suggesting no effect of ART on reoffending among adult offenders. Originally designed for adolescents, it may be that the programme should include components for more adult‐specific needs. Further, although group differences in reoffending did not emerge, research with a wider range of outcomes may be worthwhile before abandoning this approach with offenders. - 'Criminal Behaviour and Mental Health, EarlyView. '