The purpose of this study was to examine whether the early and late start typology of criminal behaviour in major mental disorder can be generalized to different populations than evaluated to date and is replicable in two different countries. A Dutch forensic sample (Sample 1) consisted of 260 reports to the court with early start offenders (n = 62) and late start offenders (n = 198). A Canadian civil psychiatric sample (Sample 2) consisted of file information collected from 78 involuntarily hospitalized civil psychiatric patients with an early start group (n = 38) and a late start group (n = 40). In both samples, early and late starters were compared on different domains. Results showed that in general, early starters have a higher risk of having problems in different domains. There were also differences in the early and late start typology between the Dutch and Canadian samples. Our results partially support the early and late starter typology within two different samples. This study showed that early starters typically have a higher risk of problems in different domains. This highlights the importance of different risk management and treatment strategies for both the early start and the late start group.