Pediatric nurses are not administering available and recommended analgesics to hospitalized children after surgery. This descriptive study was conducted to examine 30 pediatric nurses' thinking-in response to case study vignettes-about pain assessment and morphine administration for children experiencing postoperative pain. Nurses considered numerous factors when assessing and managing children's pain, including pain level, vital signs, and facial expression. Nurses frequently relied, however, on behavioral and physiological manifestations, as opposed to self-report, when choosing whether to administer morphine. Nurses demonstrated misconceptions about pharmacokinetics and unwarranted concerns about the adverse effects of morphine. These findings partly explain why children continue to report high levels of pain after surgery and why nurses may not administer adequate analgesics to relieve children's pain.