Surgery is seen as an unexpected and negative experience in the lives of patients and their relatives. During the surgical procedure, the differences in the environment and lifestyle of patients, pain, changes in the body, the possibility of individual respect or disruption of body integrity may cause them to experience anxiety and fear. Patients in the treatment and care process have difficulty meeting their sleep needs in the hospital, and their habits, attitudes and behaviors regarding sleep and rest change accordingly (Yılmaz et al. 2008). Studies have shown that hospitalized patients experience sleep deprivation (Aksu and Erdoğan 2017). Different definitions of sleep have been made; however, according to the most common definition, sleep is a state of unconsciousness during the resting of the brain and from which the person can be awakened by external stimuli (Aksu and Erdoğan 2017). Sleep, which has an important place in physical and mental health, has different aspects such as total duration, latency, regularity and quality (Pınar and Afsar, 2015; Üstün and Yücel, 2011). Sleep quality includes the quantitative (sleep latency, sleep duration, and number of awakenings per night) and qualitative (depth and restfulness of sleep) aspects of sleep (Üstün and Yücel 2011). An average of 7-8 hours of sleep is needed daily and varies according to individual characteristics such as age, gender, nutrition, activity, health status, and physical environment (Arslan 2005), and accordingly, sleep quality can be affected both quantitatively and qualitatively. In the literature, it is reported that the sleep processes of hospitalized patients are negatively affected (Şirin and Yüksel Deniz 2021; Koyuncu et al. 2021; Para and Uslu 2022); this symptom is seen in 48-90% of patients in the postoperative period (Şirin and Yüksel Deniz 2021; Oral et al. 2022); and the cause of sleep problems is often pain (Aksu and Erdoğan 2017; Oral et al. 2022). Surgical interventions affect the physiological and psychological health of patients and cause patients to experience great anxiety and fear about their lives and future (Yılmaz et al. 2008; Aksu and Erdoğan 2017). In addition, it is reported that general anesthetic drugs disrupt the sleep/wake cycle and other circadian rhythms such as body temperature and melatonin secretion (Dispersyn et al. 2009). It is stated that sleep quality is low due to reasons such as postoperative pain, anxiety about the disease and positional restrictions after the intervention (Önler and Yılmaz 2008). Short and poor sleep duration reduces uninterrupted sleep and disrupts the 24-hour circadian rhythm and normal sleep pattern. In this sense, poor sleep quality can cause multi-system effects such as increased proinflammatory cytokines, blood pressure changes, increased risk of heart attack, hormonal stress response, glucose intolerance and suppression of the immune system (Tembo and Parker 2009; Dolan et al. 2016; Bion et al. 2018; Luo et al. 2020). Therefore, the need for adequate sleep should be taken into account in both preoperative and postoperative care of surgical patients. Decreased sleep duration and quality is an important component affecting postoperative recovery (Prakrithi et al. 2019). Because when combined with surgical stress, it can lead to increased catabolic activity and tissue destruction as well as decreased anabolic activity, which in turn affects postoperative recovery (Dolan et al. 2016). Indeed, animal models have shown that sleep deprivation leads to depletion of glycogen stores and increases oxidative stress and free radical production, as well as the production of proinflammatory cytokines, all of which contribute to poor postoperative recovery. McEwen and Karatsoreos 2015; Dolan et al. 2016). In a study conducted with patients in intensive care, it was reported that on average half of the patients had sleep problems and these problems continued after discharge (Uzun and Yavşan 2014), and that sleep problems in these clinics were pain, ventilation modes, and medications (Tembo and Parker 2009). In the study conducted by Sivas et al. (2009), it was stated that there was a significant relationship between pain, sleep disturbance, and quality of life (Sivas et al. 2009). It was also determined that postoperative sleep quality was poor in patients who underwent cardiothoracic surgery and this situation lasted for more than 6 months (Caruana et al. 2018). It is stated that patients in surgical clinics have low sleep quality due to reasons such as pain, anxiety related to the disease, encountering unknowns after surgery, and positional restrictions. Determining and eliminating the factors affecting the patient's sleep needs, ensuring and maintaining a normal sleep process are among the independent nursing roles (Önler and Yılmaz 2008). The stress response shows its effects by affecting vital organs and systems such as the central nervous, circulatory, gastrointestinal and immune systems, mainly through the autonomic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis. (Dijk et al. 2020; Baek et al. 2022). Stress and the stress response can cause various clinically negative health outcomes (coronary artery disease, arrhythmia, memory problems, etc.). Numerous strategies have been developed and studied to alleviate the potential negative health effects of stress through effective management of stress with cognitive perceptual methods such as meditation, mindfulness and massage (Sharpe et al. 2007; Janssen et al. 2018; Goyal 2014). In addition to medical practices, nurses also use complementary practices to overcome symptoms such as insomnia, fatigue and pain. One of these practices, massage, is a simple, applicable, non-invasive method used to provide relaxation. The palpation of soft tissues and muscles provides both physical and mental relaxation for the person. In addition, massage is a therapeutic method that provides energy transmission between the nurse and the patient (Ünal and Akpınar 2016). Studies have reported that massage reduces physical and emotional stress and increases sleep quality, while back massage reduces pain, anxiety and sleep disorders (Dreyer et al. 2015; Boitor et al. 2017; Ünal and Akpınar 2016). It has been reported that back massage reduces cortisol levels and blood pressure, slows down heart rate and increases sleep quality (Pınar and Afşar 2015). This study was planned as a case-control study to evaluate the effect of massage applied after open heart surgery on pain, sleep quality and serum cortisol levels of patients. It is thought that the study will create literature information on the sleep quality, pain and serum cortisol levels of patients applied after open heart surgery.