Objective To compare the accuracy of post-operative pain score ratings using three numerical rating scales(NRS) between the children,nurses and parents.Methods Cognitively intact children aged five to twelve undergoing all surgical procedures were studied.Thirty-one children were included in the study.The numerical rating scale was used to rate the children's pain by the children,nirses and parents on arrival to the PACU and prior to discharge.Results We found strong correlations between children's,parent's and nurses' pain scores on admission and discharge from PACU.The intraclass correlation coefficient of pain scores reported by children and parents was 0.948(95％CI,0.897～0.975) and 0.938(95％CI,0.877～0.970).The intraclass correlation coefficient of pain scores reported by children and nurses was 0.961 (95％CI,0.922～0.981),0.972(95％CI,0.944～0.986).The intraclaas correlation coefficient of pain scores reported by parents and nurses was 0.924 (95％CI,0.850～0.963),0.921 (95％CI,0.844～0.961).Conclusions The numerical rating scale appeared to be suitable for younger children.We found strong correlations between pain scores reported by children,nurses and parents using a numerical rating scale.