Arsonists are often treated in forensic settings. However, high recidivism rates indicate that treatment is not yet optimal for these offenders. The aim of this case series study is to identify arsonist specific dynamic risk factors that can be targeted during treatment. For this study, we used patient files of and interviews with all patients that were currently housed at a forensic psychiatric hospital in the Netherlands (14 arsonists, 59 non-arsonists). To delineate differences in risk factors between arsonists and non-arsonists, scores on the risk assessment instrument the Historical Clinical Future–30 (HKT-30; completed for 11 arsonists and 35 non-arsonists), an instrument similar to the Historical Clinical Risk Management–20 (HCR-20), were compared. The groups did not differ on demographic factors and psychopathology. Concerning dynamic risk factors, arsonists had significantly poorer social and relational skills and were more hostile. Although this study needs replication, these findings suggest that the treatment of people involved in firesetting should particularly target these risk factors.