Background and Objectives - Postoperative pain is one of the major discomforts but often under treated, especially in the pediatric patient. The aim of this study was to evaluate nasal morphine postoperative analgesia as an alternative drug administration route and show its applicability, effectiveness, tolerability and side effects. Methods - Participated in this study 20 patients aged 3 to 13 years, physical status ASA I and II sequentially submitted the different small and medium-size surgeries. Analgesia was obtained with nasal morphine hydrochloride in aqueous solution in variable concentrations of 2%, 1%, 0.5%, 0.25% and 0.125%. The dose for each instillation has been 0.1 mg.kg -1 at three-hour intervals for 36 postoperative hours. Quality of analgesia in pre-verbal age patients was evaluated by a pain intensity scale based on facial expression and crying, sleep, motor activity, sociability and food ingestion was used. Standardized evaluations were performed at 3-hour intervals. A four-grade scale was used to evaluate tolerability, where: 1) Good; 2) Regular; 3) Bad; 4) Very bad. Result - Postoperative analgesia results have proven to be good and safe, especially from the third evaluation on (6 hours). Drug tolerability has been good, although side effects were observed, especially nausea and vomiting. Conclusions - Patients and relatives accepted the method very well. The nasal route was considered an adequate way for opioid administration although more studies are needed to accept it as a routine for postoperative morphine analgesia.