We investigated if carbohydrate (CHO) availability could affect the excess post-exercise oxygen consumption (EPOC) after a single supramaximal exercise bout. Five physically active men cycled at 115% of peak oxygen uptake (V̇O2 peak) until exhaustion with low or high pre-exercise CHO availability. The endogenous CHO stores were manipulated by performing a glycogen-depletion exercise protocol 48 h before the trial, followed by 48 h consuming either a low- (10% CHO) or a high-CHO (80% CHO) diet regime. Compared to the low-CHO diet, the high-CHO diet increased time to exhaustion (3.0±0.6 min vs 4.4±0.6, respectively, P=0.01) and the total O2 consumption during the exercise (6.9±0.9 L and 11.3±2.1, respectively, P=0.01). This was accompanied by a higher EPOC magnitude (4.6±1.8 L vs 6.2±2.8, respectively, P=0.03) and a greater total O2 consumption throughout the session (exercise+recovery: 11.5±2.5 L vs 17.5±4.2, respectively, P=0.01). These results suggest that a single bout of supramaximal exercise performed with high CHO availability increases both exercise and post-exercise energy expenditure.