Objective: To ascertain the extent to which community paediatricians are involved in the care of children with mental health conditions in order to determine which difficulties are appropriate for single or joint surveillance by the British Paediatric Surveillance Unit (BPSU) and Child and Adolescent Psychiatry Surveillance System (CAPSS). Design: An online survey of the 1120 members of the British Association of Community Child Health (BACCH) working in 169 Community Child Health (CCH) services in the UK. Results: A total of 245 community paediatricians responded to the survey. This represents 22% of members of BACCH but likely to have covered many of the 169 CCH units because participants could respond on behalf of other members in their unit. The survey showed that children and young people (CYP) with neurodevelopmental conditions presented more frequently to paediatrics than to Child and Adolescent Mental Health Services (CAMHS). In addition, a sizeable proportion of CYP with emotional difficulties presented to paediatricians (eg, 29.5% for anxiety/obsessive compulsive disorder (OCD), and 12.8% for depression)-mainly due to difficulty with accessing CAMHS. More than half of the community paediatricians are involved in the care of CYP with anxiety and OCD, while 32.3% are involved in the care of those with depression. Conclusion: There is significant involvement of community paediatricians in the care of CYP with mental health conditions. Involvement is highest for neurodevelopmental conditions, but also significant for CYP with emotional difficulties. The implication of the findings for surveillance case ascertainment is that joint BPSU and CAPSS is recommended for surveillance studies of neurodevelopmental conditions. However, for emotional disorders, single or joint surveillance should be made based on the specific research question and the relative trade-offs between case ascertainment, and the additional cost and reporting burden of joint surveillance. Single CAPSS studies remain appropriate for psychosis and bipolar disorder.