This study aimed to test the efficacy of imagery and relaxation in hospitalized children's postoperative pain relief. Sixty children aged 8-12 years who had undergone appendectomy or upper/lower limb surgery and had been randomly assigned to the experimental group (n1 = 30) listened to an imagery trip CD, whereas those in the control group (n2 = 30) received standard care. An investigator-developed questionnaire was used, and the intensity of pain was assessed using a visual analogue scale: before (Phase 1), immediately after (Phase 2), and 1 hour after (Phase 3) intervention or standard care. The children in the experimental group reported having significantly less pain (p < .001) than the control children based on a comparison of VAS pain scores in Phases 1 and 2. There were no significant differences in nurse-assessed pain scores. The type and time of operation were related to pain intensity in children. The nurses underestimated the pain of pediatric patients. The imagery trip CD can be used to reduce children's postoperative pain in a hospital setting, although its effect is short-lasting.