Effect of progressive muscle relaxation to the level of family stress in caring for clients of mental disorders in Psiciatry Polyclinic Regional General Hospital Kendal. Mental disorders are not contagious disease that is public health problem, both in the world and in Indonesia. In kendalthe number of mental disorders increase so increasing the level of family stress. The purpose of this study to identify the effect of progressive muscle relaxation on the level of family stress in caring for clients of mental disorders in Psiciatry Polyclinic Regional General Hospital Kendal. Quasi experiments research design pre-post test with control group with 96 sampelsby purposive sampling,48groups received therapyand 48 groups did not receive therapy. The results showed that a progressive muscle relaxation exercise significant difference between the stress levels in the group who received and did not receive therapy (p= 0.001). Tthis research did recommendated to families who are clients of mental disorders as aprimary care giver stress levels of families cope with caring for clients in mental disorders with progressive muscle relaxation therapy.