Serratus plane block was first described in 2013 by Blanco and designed to primarily block the thoracic intercostal nerves. And this block provides sufficient analgesia lateral anterior and posterior part of thoracic wall.Increased use of ultrasound guidance for regional anesthesia in recent years has led to definition of thoracic wall PECs blocks by Blanco. The Serratus plain block (SPB), providing wider analgesia, with easier application and less adverse effects than neuroaxial blocks, has been defined after these blocks and has taken its place in the literature.In spite of the insufficient randomized clinical trials in the literature, SPB has been reported for many cases such as thoracoscopy, shoulder arthroscopy, breast surgery and axillary lymph node dissections, and the results are promising. The aim of this study is to determine effectiveness of ultrasound guided bilateral serratus plane block in patients undergoing breast reduction surgery.