Screening programmes in child health have evolved on the basis of individual enthusiasm and professional consensus, rather than being based on objective evidence of benefit. Three reviews have been carried out in the UK over the past 10 years. The only programmes which show robust evidence of effectiveness are those for PKU and hypothyroidism. The value of screening for hearing loss and vision defects is widely accepted, but there are many unresolved issues. Programmes for detection of congenital dislocation of the hip, congenital heart disease and growth disturbances are of doubtful value. Early identification of developmental problems is stressed by parents, but screening may not be the best way to achieve this. The UK programme of well-child care places increasing emphasis on promotion of physical and emotional health; screening tests should either be subjected to quality monitoring, or removed from the programme if they cannot fulfil the classic criteria of Wilson and Jungner.