OBJECTIVE Studies on the ecology of medical care for children have been reported only from the United States. Our objective was to describe proportions of children receiving care in 6 types of health care utilization seeking behaviors in Japan on a monthly basis and to identify care characteristics. METHODS A population-weighted random sample from a nationally representative panel of households was used to estimate the number of health-related symptoms, over-the-counter medicine doses, and health care utilizations per 1000 Japanese children per month. Variations in terms of age, gender, socioeconomic status, and residence location were also examined. RESULTS Based on 1286 households (3477 persons including 1024 children) surveyed, on average per 1000 children, 872 had at least 1 symptom, 335 visited a physician's office, 82 a hospital-based outpatient clinic, 21 a hospital emergency department, and 2 a university-based outpatient clinic. Two were hospitalized, and 4 received professional health care in their home. Children had 2 times more physician visits and 3 times more emergency visits than adults in Japan, and Japanese children had 2.5 times more physician visits and 11 times more hospital-based outpatient clinic visits than US children. Pediatric health care utilization is influenced significantly by age but not affected by income or residence location in Japan. CONCLUSIONS Compared with the data from the United States, more children in Japan visit community physicians and hospital-based outpatient clinics. Results of this study would be useful for further delineation of health care utilization of children in the context of a health care system unique to Japan.