Two thousand forty-four emergency department (ED) visits were made during a one-year period by 714 children enrolled in a primary care clinic. Eight hundred one (39.2%) visits were for urgent or emergent conditions, and 579 (28.3%) were for presenting complaints suggestive of urgent or emergent conditions, including 65 based on parental concern. Six hundred sixty-four (32.5%) visits might have been considered medically inappropriate using criteria specifically developed for this study. These criteria were developed as a standard which might be used for future studies on ED use by children. Children without medical assistance and those over 12 months of age were more likely to be consistently appropriate users. Appropriateness of use was not associated with the patient's race, sex, distance of home from the hospital, telephone availability, length of clinic enrollment, type of primary provider, or chronic disease other than asthma. Further, medical assistance recipients were more likely to make three or more inappropriate visits than were the other groups.