PURPOSE: To investigate the effect of the menstrual cycle (MC) on exercise performance across the power-duration relationship (PDR). We hypothesized females would exhibit greater variability in the PDR across the MC than males across a similar timespan, with critical power (PCRIT) and Work prime (W') being lower during the early follicular phase than the late follicular and mid-luteal phases. METHODS: Eumenorrheic, endurance-trained females (n = 10, age = 24.1 ± 5.59) performed multiple constant-load-to-task-failure and maximum-power tests at three time points across the MC (early follicular, late follicular, midluteal phases). Endurance-trained males (n = 10 age = 29.5 ± 9.18) performed the same tests approximately 10 days apart to mimic the time between the phases of the MC. RESULTS: No differences across the PDR were observed between MC phases (PCRIT: 175.66 ± 34.97 W, P = 0.632, CV = 1.28 ± 0.97 %) (W': 7916.53 ± 2316.69 J, P = 0.283, CV = 13.56 ± 6.93 %). PCRIT was similar for males and females (11.82 ± 1.44 W • kg-1 vs. 11.20 ± 1.82 W • kg?1, respectively) when controlling for leg lean mass. However, W' was larger (P = 0.048) for males (617.28 ± 130.10 J • kg?1) than females (505.24 ± 137.66 J • kg?1). CONCLUSION: These findings indicate that researchers do not need to account for MC phase when conducting performance research on female subjects. Nevertheless, factors, such as body size and leg lean body mass, do limit exercise performance in males and females. As such, previous studies looking at factors limiting exercise performance in males may not always apply to females.