Remifentanil is a potent, selective, 4-anilidopiperidine µ- opioid receptor agonist not licensed for analgesia in the maintenance of general anesthesia in pediatric subjects in Japan. A phase III trial was conducted to evaluate remifentanil for pediatric subjects in Japan. This multicenter, open-label, one-arm study in pediatric subjects between 1 and 15 years of age receiving general anesthesia included 80 subjects. Nine subjects (11.3%) showed response to skin incision, which was the primary endpoint, and no apparent difference in response rate was found according to age (1–6, and 7–15 years old). Drug-related treatment emergent adverse events were found in 24 subjects (30.0%) with the most common event being heart rate decreased (26.3%). Remifentanil was found to be effective and safe for analgesia in maintenance of general anesthesia for pediatric subjects.