Cholecystectomy is a widespread surgical procedure performed worldwide for acute cholecystitis. This operation can be performed using open surgery or laparoscopic techniques. Laparoscopic technique is superior to open surgery in terms of less pain at incision sites, shorter hospital stay, improved quality of life, and faster recovery times.However, despite being a minimally invasive surgery, laparoscopic cholecystectomy (LC) can still cause moderate to severe pain. Severe pain can lead to delayed postoperative ambulation, decreased patient satisfaction, the development of chronic pain, and is associated with increased lung and heart complications. Postoperative pain in LC can stem from various causes. To reduce the postoperative pain caused by LC, non-steroidal anti-inflammatory drugs, paracetamol, opioids, local anesthetics, and various regional anesthesia techniques are used.Multimodal analgesia has shown that the use of regional anesthesia and analgesia is crucial in reducing the neuroendocrine stress response in pain and trauma situations. The use of interfascial plane blocks performed under ultrasound guidance in LC surgery, considered easy and safe, has increased in recent years. The thoracoabdominal plane block (TAPA) applied through a perichondrial approach reaches a broader dermatomal area than the transversus abdominis plane (TAP) block and the oblique subcostal transversus abdominis plane (OSTAP) block.Serratus intercostal plane block (SIPB) has been found effective for somatic analgesia in a case series after gastrectomy and cholecystectomy surgeries. Subsequent studies have indicated the effectiveness of SIPB for open upper abdominal surgeries. Rectus sheath block (RSB) is used to provide postoperative analgesia after various surgeries, including laparoscopic and upper abdominal surgeries. Ultrasound-guided RSB in LC has significantly reduced postoperative pain.In this study, similar to the combination of RSB and SIPB was planned to be applied to enhance the effectiveness and quality of analgesia in the mid-abdomen. A group in LC surgery was administered bilateral M-TAPA, while another group received bilateral RSB + right SIPB, aiming to compare the postoperative analgesic effectiveness.