Title: Analysis of load referee during basketball games in different age and performance level. Objectives: Record heart rate, run the distance, match time, load zone of selected referee during basketball games. Gathered data compare between different competition levels. Methods: Analysis of outcomes gathered based on measurements of basketball referee during basketball games using sport tester RS800 and Nike iPod sensor. Measurements where gathered during season 2014/15 in the range of 48 measurements. Results: Research prove that the heart rate of basketball referee differ based on what level and competition she supervised. Expected hypothesis was proved that with growing category grow average heart rate, consequences of this fact is longer distance run during the game which means faster pace of the game and growing mental load which impact the referee. Keywords: rules, match, sport tester, heart rate, load zone, nervousness, player, coach, match time, category, competition