Adolescence is the period of transition from childhood to adulthood. This period is marked by physical, mental, emotional and cognitive development. Physical activity has a positive effect on all elements of development during adolescence. The World Health Organization defines physical activity as any movement performed by skeletal muscles that requires energy expenditure, and motivation has an important impact on physical activity. The purpose of this thesis is to determine the level of physical activity of adolescents and to determine the motives for participation in physical activity and exercise. The research was conducted in the period from May and June 2021 at The Zagreb Health School . The study involved 351 students studied for vocations in the field of medicine for dental assistant, dental technician, pharmacy technician, physical therapy technician, medical cosmetician, sanitary technician and medical laboratory technician. The Physical Activity Questionnaire for Adolescents (PAQ-A) was used to assess the level of physical activity, and the Exercise Motivations Inventory – 2 (EMI-2) was used to examine the motives for participating in physical activity and exercise. The results showed a low level of physical activity in the subjects. A statistically significant difference was found in the level of gender-related physical activity. Age, grade, and field did not have a significant effect on the level of physical activity. The highest average values were recorded for subscale positive health and strength and endurance. A statistically significant difference in motives related to gender and age was observed in the subscales associated with intrinsic motivation, and in class and direction a statistically significant difference was observed in the subscales associated with extrinsic motivation.