Background and Purpose: A unilateral paravertebral (PVB) block with catheter can provide extendable analgesia without physiological changes. The objective of this study was to assess the efficacy of PVB bupivacaine for providing perioperative pain relief in adults undergoing percutaneous nephrolithotomy (PCNL) under general anesthesia. Methods: Fifty American Society of Anesthesiologists Grade I, II patients, aged 18 to 65 years, were included in this prospective, randomized, controlled, observer blinded trial. PVB group patients received preinduction 20 mL of 0.5% bupivacaine in the T9-10 paravertebral space and a catheter in addition to general anesthesia. Control group patients received only general anesthesia. All patients received intravenous fentanyl (2 μg/kg on induction, 0.5 μg/kg on 20% increase in heart rate or mean blood pressure) and paracetamol every 6 hours. Postoperative pain was assessed using the visual analog scale (VAS) (0-10 cm) at rest and movement by a blinded observer at 0, 1, 2, 4, 6, 12, and 24 hours postoperatively. Results: Data of 48 patients were analyzed. Intraoperative fentanyl requirement was higher in the control group (2.74±0.75 μg/kg [95 % confidence interval (CI) 2.42, 3.05]) than the PVB group (2.07±0.26 μg/kg [95 % CI 1.96, 2.18]), (P=0.0001). Time to first postoperative analgesic requirement was longer in the PVB group (120 min [30-570]) than the control group (30 min [0-180]), (P=0.0000). The VAS on rest (0, 1, 2, and 12 h) and movement (all time points) were significantly lower in the PVB group. Postoperative fentanyl consumption was lower in this group (175 μg [25-475]) compared with the control group (525 μg[(150-1275]), (P=0.0000). Conclusions: Unilateral PVB block with catheter provided effective perioperative analgesia for PCNL.