Dehydration is defined as deficit in total body water and has been suggested to have adverse effects on athleticperformance as well as health. Despite ongoing efforts to inform the athletes, especially weight-classified athletes presenthigher level of dehydration. As judo is a weight-classified sport and athletes are exposed to rapid weight loss methods,hydration status of judo athletes should be monitored for athletes’ health and implications for future precautions. Thus, the aimof this study was to monitor hydration status of elite judo athletes during a competition day. Eighteen (13 males, 5 females) elitejudo athletes voluntarily participated in this study. Following body composition measurements, USG and urine colormeasurements were carried out before and after the competition in order to determine their hydration status. Athletes’ prematch USG value was 1,021 while it was found 1,019 after competitions. As for urine color, it was 5,17 before competitions and4,87 after competition. According to these results elite judo athletes presented higher level of dehydration during a competitionday despite ad libitum fluid intake. Judo athletes and coaches should be informed about adverse effects of dehydration andindividual water intake prescriptions for these athletes can be advised. Further research is also advised to confirm thatdehydration negatively affects judo specific performance.