Although the developmental perspective has become a leading paradigm in criminology, little attention has been paid to the onset of offending and life course of murderers within this tradition. We use bivariate and Multiple Correspondence Analysis to investigate the life course and criminal careers of three onset groups among a UK sample of 786 men convicted of murder. The early-onset group (20% of the sample) is more likely to have experienced significant problems in childhood and adulthood. The no-offending group (10% of the sample) is the least likely to have had problematic backgrounds. The childhoods of the late-onset group (67% of the sample) resemble the no-offending group (with few problems) but in adulthood they more closely resemble the early-onset group (with many problems). The implications of these findings for developmental criminology and homicide research are discussed. © 2007 Sage Publications.