One of the challenges for clinicians is to identify those infants who are at risk of later psychopathology and to intervene at an early stage. The study of negative life events for children from birth to three years of age has been comparatively neglected despite the fact that the fields of psychoanalysis, forensic psychology, developmental psychopathology and neuro-psychology all emphasis the importance of the early years. Aim: Drawing from the literature, this study examined life events that disrupt the first attachment relationship and proposed that early behavioural difficulties in children are the result of the stress and trauma consequently experienced. Method: A Life Events Checklist was designed and used as a measure in two cross sectional studies that examined the nature and incidence of life events occurring to children between birth and three years [a] in a clinical sample [N = 123] and [b] in a community sample [N = 193]. Events occurring in the three year period prior to referral were also recorded in the clinical study. Results showed that children in the clinical study experienced a high number of life events across time although more event were experienced in the first three years than in the three years prior to referral. Logistic regression analysis applied to both sets of data indicated an event of loss, a disturbed relationship and/or a trauma in the first 18 months of life could predict later mental health problems. The data showed that Health Visitors were less likely to express concerns at this early stage. The implications of the study for early assessment and intervention are discussed. Clinical interventions with children referred to child mental health services need to address symptoms of stress and trauma through the limbic system rather than through cognitive and behavioural approaches alone.