Background: Many studies have described associations between adult psychiatric disorder among adults and their biographic, socio-demographic and social capital characteristics. Fewer studies have focused on children, and most of these have looked at structural indicators of the neighbourhood. Our objective was to examine one aspect of social capital--perceived neighbourhood trust and safety in relation to childhood psychopathology. Methods: Data on childhood psychopathology and perceived neighbourhood trust and safety were obtained on 3,340 11 to 16-year-olds included in a large survey of the mental health carried out in 426 postal sectors in Great Britain. Data were collected on biographic and socio-demographic characteristics of the child and the family, measures of social capital and neighbourhood prosperity. We entered all these variables into a logistic regression analysis to establish the strength of association between perceived neighbourhood trust and safety separately for emotional and conduct disorders. Results: Children's perception of their neighbourhoods in terms of the trustworthiness or honesty of the people who live there or feeling safe walking alone had a strong association with childhood psychopathology, particularly emotional disorders, rather than the nature of the neighbourhood itself. Children's behaviour, however, such as going to the park or shops alone, did not vary by measures of childhood psychopathology. Conclusions: Regeneration of less prosperous neighbourhoods is likely to increase children's positive perceptions of trust, honesty and safety which in turn can have a positive effect on their mental health.