INTRODUCTION: Pain is a subjective experience. In children with limited understanding and communication skills, reliable assessment of pain is challenging. Self-reporting of pain is the gold standard of pain measurement. For children who are unable to self-report their pain, assessments made by their parents are often used as a proxy measure. The validity of this approach has not been conclusively determined. AIM: To investigate differences in the assessment of pediatric pain between children, parents, nurses, and independent observers in the acute postoperative setting. METHOD: Three hundred and seven children (207 verbal, 100 nonverbal) undergoing elective day-case surgery were asked to participate in this quality of care audit. Pain scores given by verbal children, their parents, nurses, and independent observers were collected. A numerical rating scale or the Wong-Baker Faces Pain Scale was used. All participants were blinded from other scorers. RESULTS: For verbal children, scores reported by patients and their parents did not differ significantly. Median [inter-quartile range (IQR)] scores by children, parents, nurses, and independent observers were, respectively, 2.0 (0-4.0), 2.0 (1.0-4.0), 0.0 (0-2.0), and 1.0 (0-2.0). In nonverbal children, median (IQR) scores by parents, nurses, and independent observers were 1.0 (0-3.0), 0 (0-1.0), and 0 (0-2.0), respectively. The agreement between the different scorers was statistically significant. CONCLUSION: Children's pain self-reports should be used wherever possible to guide management, but in their absence, parental pain scores can be reliably used as a surrogate measure. Nurses and independent observers produce lower pain scores than parents or children, which may result in inadequate treatment of pain.