The aim of this study was to investigate the effects of preemptive ultrasound-guided thoracic paravertebral block versus intercostal block on postoperative respiratory function and pain control in patients undergoing video-assisted thoracoscopic surgery.50 consecutive patients undergoing video-assisted thoracoscopic surgery.A prospective cohort of patients who received either ultrasound-guided thoracic paravertebral block immediately before the procedure or intercostal block placed by the surgeon at the end of the procedure were studied. Pulmonary function was assessed before surgery and 4 h postoperatively. Pain was assessed with the visual analog scale at 2 and 4 h after surgery both at rest and on coughing.30 patients on the paravertebral block group and 20 on the intercostal block group were studied. Forced vital capacity (p < 0.001), forced expiratory volume at 1 s (p < 0.001) and forced expiratory flow 25-75% (p = 0.001) were significantly higher at 4 h with paravertebral block compared to the intercostal block group. The visual analog score for pain was significantly improved with paravertebral block at rest (p < 0.05) and with cough (p = 0.00). Perioperative narcotic use was significantly reduced with paravertebral block in comparison to intercostal block (p = 0.04).When compared to intercostal blocks, ultrasound-guided thoracic paravertebral block appears to preserve lung function and provide better pain control in the immediate postoperative period after video-assisted thoracoscopic surgery.