Physical activity is related to health factors such as motor competence, health related  Physical fitness, perceived motor competence. The purpose of this study was to investigate the role of mediation of cardiovascular fitness, perceived motor competence in relation between actual  motor competence and physical activity of boys in middle and end childhood.  Research is a correlation type. 204 students (mean age 9.9 and standard deviation of 1/05) from the four Tehran schools participated in this study. The motor competence was measured using the Bruninks-Oseretsky-based product-oriented (BOT-2), perceived motor competence, and physical activity, using the PSDQ and the physical activity questionnaire for older children (PAQC), respectively. The 600 yard running / walking test was used to measure cardiovascular endurance.   Pearson's test results showed a moderate to weak relationship between all variables. Also, the results of regression path analysis indicated that perceived motor competence, not cardiovascular fitness, mediates the relationship between real motor competence and physical activity. Educational and practice strategies should target the development of fundament motor skills and perceived motor competence to increase the participation of male students in the physical activity.