We compared the care delivered to children by pediatricians and general practitioners, using data from the National Ambulatory Medical Care Survey (NAMCS). These two types of physicians provide almost three fourths of all office-based care for children under 15 years old. Pediatricians saw more very young children and fewer adolescents than did general practitioners. They provided more constant care over time and more routine preventive care in all age groups, and they made more diagnoses in children seen for this latter type of care. The distribution of other reasons for visits was the same for both types of physicians. For most of the common presenting problems, pediatricians ordered more laboratory tests but prescribed fewer drugs. The data suggest that general practitioners were more immediately accessible than pediatricians. Although the implications of these findings require further exploration, these differences in the constancy and accessibility of care, frequency of diagnoses made, and costs of commonly ordered laboratory tests may affect the quality, effectiveness, and efficiency of children's health care.