Thoracotomy is one of the most painful operations known. Therefore, it causes severe acute pain. If pain is not controlled, it increases the frequency of postoperative pulmonary complications and postoperative morbidity. It can even cause chronic pain in the future. Thoracic epidural analgesia (TEA) is the gold standard method in the treatment of pain after thoracotomy. Thoracic paravertebral block (TPVB) is known as the most effective method after TEA. The fact that TPVB has fewer side effects than TEA increases the use of TPVB. There is no consensus on the dose of analgesia in studies. In the literature, volumes between 20 ml and 30 ml are frequently used for TPVB in recent years. This study, it was aimed to compare the efficacy of 20 ml, 25 ml, and 30 ml volumes of TPVB with local anesthetic at the same concentration (0.25% bupivacaine) on postoperative analgesia in patients undergoing thoracotomy.