The aim of this study was to determine the influence of a dedicated training course on the ability of participants to assign correct codes and their inter-observer agreement using the Abbreviated Injury Scale (AIS98). Twelve participants followed a one-day training course in injury coding. Codes were recorded before, during and after the course. The number of correctly assigned codes and severity codes, as well as the Fleiss' kappas improved significantly during and after the course. This study emphasises the benefit of training in injury coding. Training improves the ability to assign correct codes and it reduces inter-observer variability. We advise all who are involved in injury coding to follow a dedicated training course.