In order to maintain performance, training is a must and there is no exception during the compulsory yearly Ramadan fasting, specifically for Muslim athletes. However, studies have shown that Ramadan fasting which causes significant changes in calories intake affect blood glucose concentration thus athlete’s performance. It is the purpose of this study to investigate the blood glucose levels of fasting and non-fasting competitive endurance athletes before and after endurance test during Ramadan fasting month. Eight subjects (fasting, n= 4, non-fasting, n= 4) with an average age of 23.1±3.0 years, height of 167.0±6.6 cm, weight of 56.5±7.4 kg and BMI of 20.2±2.1 participated in the study. All subjects were competitive runners who are continuously involved in the annual MALAKOFF University Dualthon Series since the past two years. For this study, subjects were required to complete 2.4 km run test at their fastest pace, three times with rest at least two days between each trial. Measurements were pre-and post-run blood glucose (Accu check, Performa, Roche Diagnostics NZ Ltd, New Zealand), heart rate monitoring (Polar Heart Rate, Polar Electro Oy, Finland) and performance time. Gathered data were analyzed using independent t-test via Statistical Package for Social Science version 14.0 (SPSS 14.0) in order to compare the result between fasting and non-fasting groups. The pre-run blood glucose of the fasting group (4.9 mmol/L±0.4) was lower than the non-fasting group (6.2 mmol/L±0.7), similar to a study by Bouhlel et al.(2008)[4.8 mmol/L±0.4 (1st week Ramadan) and 4.8 mmol/L±0.4 (final week Ramadan)] but higher than the study by Nomani et al.(1989)[4.51 mmol/L±0.67 (day 15) and 4.24 mmol/L±0.34 (day 28)]. Results indicated a significant difference of pre-run blood glucose (t=-3.08, p=. 022) between groups but not on the postrun blood glucose. In terms of performance time, the fasting group clocked 11.63±1.87 minutes, and the non-fasting group 11.12±0.94 minutes which shown no significant difference with t=. 488, p=. 643. These showed that maintaining blood glucose level during fasting is unnecessary for performance continuation but might be important for health purposes.