Background: Mental health problems cause a disproportionate burden of disability among children and youth compared to adults. Primary care plays an important role in efforts to prevent and intervene early in the course of child and adolescent mental health problems. While research with adults has shown the feasibility of integrating mental health care into primary care settings, there have been few studies among children and youth. Evidence remains lacking that integration is feasible in diverse settings, that it improves outcomes, and that methods can be developed to address the mixed symptoms of emerging child/youth problems and their overlap with developmental and parental disorders.