Background: Physical inactivity is a public health problem in Saudi Arabia. Physical inactivity is associated with several chronic diseases, increased medical care costs and premature death. Objectives: To determine the pattern of physical activity, the predictors of physical inactivity and the perceived barriers of physical activity among students in College of Medicine at Al-Jouf University, Saudi Arabia. Methods: A cross sectional study was carried out among 283 medical students in the age group of 19-33 years. The Arabic short form of International Physical Activity Questionnaire (IPAQ) was used to measure physical activity. Analysis was done according to the guidelines for data processing and analysis of the IPAQ. Results: Overall, 60.1% of the students were physically inactive. Only 38.2% of the students performed vigorous physical activity, 21.9% moderate-intensity physical activity and 33.2% walking activities, which met World Health Organization criteria of health-enhancing physical activities. The significant predictors of physical inactivity were low father education, dead or retired father, mothers not working for cash, families with five members or more and non-participation in sports clubs. The significant barriers of physical activity among physically inactive students were time limitations, lack of money, lack of safe sport places, not being interested in sports and body cannot tolerate physical activity. Conclusion: The majority of medical students of Al-Jouf University in Saudi Arabia are physically inactive. Overcoming perceived barriers may increase physical activity among university students