. Hospitalization of children is a response to changing situations that cause stress. Children who are hospitalized are not comfortable with the environment, separation from parents and peers, activity limitation, bodily injury and pain. Stress management can be overcome by providing psychotherapy, such as music therapy. Music therapy can also improve mental function, accelerate healing, improve the sense of well-being. The purpose of this study was to determine the effect of music therapy on the stress of hospitalization in school age children in the hospital dr.Pirngadi Medan. The study design using a quasi-experimental with pre-post test design. The sampling technique is total sampling and sample number 31orang. Data were analyzed using the Wilcoxon test. The results of the study before it is given music therapy than average scores and standard deviations stres11.61 2,155 children. After being given music therapy an average score of stress 1:16 and a standard deviation of 3.606. Statistical test results obtained by the P value of 0.000 was concluded that there was an effect of music therapy on the stress of hospitalization in school age children. This study proves that music therapy can reduce stress in children. It is recommended to apply this therapy as one intervention in providing nursing care in children.