In our study we compared sufentanil vs fentanyl in children undergoing Lich–Gregoir antireflux plasty. The aim of this study was to evaluate and compare the hemodynamic parameters during anesthesia as well as the time of extubation of both opioid analgesics. Patients were included in two groups of 20 patients: group I, sufentanil and group II, fentanyl (mean age 5.42 ± 3.25 years; mean body weight 15.87 ± 4.02 kg). All were premedicated with midazolam 0.2 mg/kg intranasally, 10 min before induction of anesthesia. Anesthesia was induced with sufentanil 0.5 μg/kg (group I) or fentanyl 2 μg/kg (group II) and propofol 3–4 mg/kg, followed by vecuronium 0.1 mg/kg. Anesthesia was maintained using isofluorane in oxygen and nitrous oxide. In group I sufentanil was administered in the dose of 1 μg/kg intravenously prior to skin incision. In group II fentanyl was administered in the dose of 1 μg/kg intravenously at the same time. Hemodynamic parameters such as systolic and diastolic blood pressures and heart rate were recorded. Following induction of anesthesia and tracheal intubation, hemodynamic parameters in group I did not increase. During intubation patients in group II showed an increase of measured hemodynamic parameters. The average time before postoperative tracheal extubation was 62.20 ± 15.55 min in the sufentanil group and 75.27 ± 10.20 min in the fentanyl group, which was statistically significant. In the ICU pain and overall satisfaction were assessed with a 10-point visual scale. There was no difference in the requirements for pain relief. Our study showed that sufentanil versus fentanyl in an appropriate dose does not change hemodynamic parameters during anesthesia induction. Postoperative requirements for pain relief were the same in both opioid analgesics.