Postoperative pain is a significant problem in patients undergoing arthroscopic shoulder surgery. This situation disrupts the patient's comfort and affects the functional outcome after surgery by preventing early rehabilitation. Various methods are used for postoperative pain control. Intravenous opioid agents are one of the most commonly used analgesic techniques. However, opioids can cause undesirable side effects such as respiratory depression, sedation, constipation, allergic reactions, nausea, and vomiting. Therefore, alternative techniques are needed to reduce opioid use. Serratus posterior superior interfascial plane block (SPSIPB) is a novel interfascial plane block described by Tulgar et al in 2023. It is based on injection into the serratus posterior superior muscle at the level of the 2nd or 3rd rib. This block provides analgesia in cases such as interscapular pain, chronic myofascial pain syndromes, scapulocostal syndrome, and shoulder pain. It has been reported that SPSIPB provides effective shoulder analgesia.