BACKGROUND/AIMS: Many block methods have been applied for postoperative analgesia after laparoscopic cholecystectomy (LC).We aimed to compare the effectiveness and reliability of thoracic paravertebral block (TPVB) and erector spinae plane block (ESPB) performed with ultrasonography in elective LC cases on postoperative analgesia. MATERIALS AND METHODS:This study was carried out as a randomized double-blinded prospective study.We divided 102 patients who would undergo elective LC into 2 groups (TPVB; group 1, and ESPB; group 2) using a website (www.randomizer.org)with 51 patients each.We applied the blocks unilaterally with 20 mL of 0.25% bupivacaine at the T-8 level under the guidance of ultrasound.Postoperative visual analog scale scores, additional analgesic requirements up to the 24 th hour, the duration of block application, postoperative nausea and vomiting data, and any developing complications were noted. RESULTS:Hundred and two patients (51 patients in each group) were evaluated.We found no statistically significant differences in age, gender or comorbidities (p>0.05).Postoperative resting and dynamic visual analog scale scores did not differ statistically (p>0.05).When the presence of nausea and vomiting, complication rates, the duration of the block application and postoperative first analgesic requirements were compared, we found no significant difference between the groups (p>0.05 for each).The satisfaction score was found to be significantly higher in group 1 (p=0.011). CONCLUSION:We determined that ultrasound guided TPVB and ESPB were not superior to each other in terms of postoperative analgesic potency in LC.However, ESPB is a newer block, simpler to administer and not inferior in analgesic efficacy compared to TPVB.