ABSTRACT The Effect of Deep Breath Relaxation on Decreasing Chest Pain in NSTEMI Patients in the ICCU Room at the Klungkung District Hospital Ni Wayan Sukrimi1, Ns. Ni Komang Sukraandini, S.Kep., MNS2, Anak Agung Gde Oka Widana, SPd.H., M.Pd.H3 NSTEMI is part of Acute Coronary Syndrome with typical symptoms of persistent retrosternal chest pain such as pressure from heavy objects. This disease is the main cause of all deaths in developing countries, including Indonesia. Handling chest pain in addition to using pharmacological therapy, can also be treated with non- pharmacological therapy, one of which is deep breathing relaxation. Deep breathing relaxation can reduce chest pain through the mechanism of relaxing the muscles that experience spasm caused by prostaglandins, resulting in vasodilation which increases blood supply to tissues that experience spasm or ischemia. The aim of this study was to determine the effect of deep breath relaxation on reducing chest pain in NSTEMI patients. This type of research is preexperimental with one group pretest post-test design. The number of samples is 10 people with purposive sampling. Data collection using the Numerical Rating Scale pain scale. The results showed that the average scale of chest pain before being given deep breath relaxation was 4.2, while after being given breathing relaxation the average pain scale was 1.5. Deep breathing relaxation performed 2 times a day for 3 days with a duration of 5-15 minutes can reduce chest pain as evidenced by the results of the Wilcoxon test analysis obtained p value = 0.004 (α = 0.05), which means that p value <0.05, so that there is an effect of deep breathing relaxation on reducing chest pain in NSTEMI patients in the ICCU Room at the Klungkung District Hospital. The research conducted by the authors found that deep breathing relaxation can reduce the chest pain scale on average 2-3 scales lower than the previous chest pain scale. Key words: deep breath relaxation, chest pain, NSTEMI