Introduction: Kyphosis is generally defined as a disease that occurs in the area of the vertebrae or the human spine which causes a hunched posture. As for some musculoskeletal complaints caused by kyphosis, including changes in body posture that bends forward so that it affects appearance, pain is felt in the spinal area, muscles get tired easily, and tightness in the back area, which in the most severe conditions kyphosis can cause problems in the respiratory tract and other organs. The cause of kyphosis is caused by several factors, namely body mass index, workload, disease scheurman,and birth defects. This study aims to determine whether there is a relationship between Body Mass Index and Physical Activity with the Incidence of Kyphosis in Physiotherapy Students at the Faculty of Medicine, Udayana University. Method: This research is a type of descriptive analytic research approach cross-sectional, using the total sampling technique, the number of subjects was 64 physiotherapy students who met the exclusion and inclusion criteria. Data was taken by measuring body mass index using the BMI formula, using global physical activity questionnaire (GPAQ) to measure physical activity, flexicurve as a measure of the degree of kyphosis.