To compare the effects of ultrasound-guided thoracic paravertebral block (PVB) and intravenous paracetamol on postoperative pain control in paediatric patients undergoing percutaneous nephrolithotomy (PNL).Forty patients aged 1-5 years, with an American Society of Anesthesiologists physical status I-II, scheduled for PNL were enrolled into this prospective randomised controlled trial. After arrival in the operating room, all patients were administered standardised general anaesthesia. Patients in Group PVB received ultrasound-guided PVB using bupivacaine 0.5% at a total volume of 0.5 mL kg at the vertebral levels T11, T12 and L1. Patients in Group P were administered paracetamol intravenously (15 mg kg) before the beginning of surgery. Patients in both groups were given tramadol (1 mg kg) for supplemental analgesia. Patient demographics, haemodynamic parameters, peripheral oxygen saturation and sevoflurane concentration were recorded. The Face, Legs, Activity, Cry and Consolability pain scores; satisfaction of parents; the number of patients requiring supplemental analgesia; and complications were evaluated during the postoperative period.Pain scores were significantly lower in Group PVB compared with Group P (p=0.001). There were no analgesic requirements in Group PVB; however, all patients needed a supplemental analgesic in Group P. Parental satisfaction was higher in Group PVB than in Group P.This study demonstrated that ultrasound-guided PVB provides more effective postoperative analgesia with no side effects compared to intravenous paracetamol in children undergoing PNL.