Well-child care is a near-universal service for young children toward which a great deal of time and professional resources are devoted but for which there is scant evidence of effectiveness in routine practice. It is composed of many components, the value of which likely varies with the quality of their provision and the needs and priorities of the children and families who receive them. Achieving more efficient and effective preventive care will require that pediatric practices segment the population they serve and design schedules and staffing to match patients' health, well-being, personal and social circumstances, and service needs. Care should be individualized and include essential screening, tests, procedures, and education on the basis of assessment of patients' and families' needs and priorities. The traditional schedule of individual, comprehensive preventive care visits should be reconsidered and replaced with a schedule that allows complete care to be provided over a series of visits, including those for acute and chronic care. Preventive pediatric care should be provided in family-centered, team-based practices with strong linkages to other providers in the community who serve and support children and families. Care should make use of the wide variety of modalities that exist, and face-to-face time should be reserved for those services that are both important and uniquely responsive to in-office intervention. This model of preventive care will require changes in training, responsibilities and reimbursement of health care team members, and enhanced communication and collaboration among all involved, especially with families.