Background: Cardiorespiratory fitness is the ability of the cardio and pulmonary to supply oxygen to the whole part of the body tissues during physical activity. There are several studies about the association of cardiorespiratory fitness and mental health such as deprresion, anxiety, and stress. But the studies is still limited. It encourages researchers to find out how the correlation between stress level and cardiorespiratory fitness level in medical students. Method: The design of this study was an analytic study with a cross sectional approach. Total of sample is 34 medical students in Muhammadiyah University of Yogyakarta, was taken using a purposive sampling method. Stress levels were measured using Depression, Anxiety, Stress Scale (DASS) 42 questionnaire, and cardiorespiratory fitness levels were measured indirectly by Harvard Step Test method. Result: The result of statistical analysis using the Spearman correlation test showed there is a significant relationship between stress levels and cardiorespiratory fitness levels (p=0,047<0,05), with the direction of a positive relationship is weak (r=0,343). Conclusion: Based on this cross sectional study, there is a positive significant relationship between stress levels and cardiorespiratry fitness levels in final-year medical students in Muhammadiyah University of Yogyakarta.