Non-attendance of families is a common problem in child and adolescent mental health services (CAMHS). We report on the development and pilot evaluation of a pre-intake intervention designed to enhance initial engagement at inner-city CAMHS in London, UK. Families receiving the intervention (N = 107) were significantly less likely to miss first appointments compared with contemporaneous (N = 62) or historical (N = 163) control groups. The intervention had similar effects for white and minority ethnic families, and for those from the most and least deprived parts of the locality. Recommendations are made for routine provision of empirically-supported engagement strategies, informed by consultations with service users and providers.