The 12-member American Burn Association/Shriners Hospitals for Children Outcomes Task Force was charged with developing a health outcomes questionnaire for use in children 5 years of age and younger that was clinically based and valid. A 55-item form was tested using a cross-sectional design on the basis of a range of 184 infants and children between 0 and 5 years of age at 8 burn centers, nationally. A total of 131 subjects completed a follow-up health outcomes questionnaire 6 months after the baseline assessment. A comparison group of 285 normal nonburn children was also obtained. Internal consistency reliability of the scales ranged from 0.74 to 0.94. Tests of clinical validity were significant in the hypothesized direction for the majority of scales for length of hospital stay, duration since the burn, percent of body surface area burned, overall clinician assessment of severity of burn injury, and number of comorbidities. The criterion validity of the instrument was supported using the Child Developmental Inventories for Burn Children in early childhood and preschool stages of development comparing normal vs abnormal children. The instrument was sensitive to changes over time following a clinical course observed by physicians in practice. The Health Outcomes Burn Questionnaire for Infants and Children 5 years of age and younger is a clinically based reliable and valid assessment tool that is sensitive to change over time for assessing burn outcomes in this age group.