Research on the assessment and management of pain in infants and children has increased dramatically, with the consequence that a wide variety of behavioral, physiological, and psychological methods are now available for measuring pediatric pain. Although the criteria for a pain measure for children are identical to those required for any measuring instrument, special problems exist in pediatric pain measurement because the influence of developmental factors, previous pain experience, and parental attitudes on children's perceptions and expressions of pain is not known. This article reviews the recent advances in the measurement of pain in children, with special emphasis on the methods that satisfy the criteria for reliability and validity, the methods that can be used to assess multiple dimensions of pain, and the methods that may be appropriate for assessing all types of acute, recurrent, and chronic pediatric pain.