Aim: The aim of the current study was to assess whether executive function and prefrontal oxygenation are dependent on fitness level and age in older adults. Methods: Twenty-four healthy males aged between 55 and 69 years old were recruited for this study. They were stratified by age, leading to the creation of two groups: 55â€“60 years old and 61â€“69 years old. A median split based on CRF created higher- and lower-fit categories of participants. Cerebral oxygenation was assessed using functional near-infrared spectroscopy (fNIRS) during a computerized Stroop task. Accuracy (% of correct responses) and reaction times (ms) were used as behavioural indicators of cognitive performances. Changes in oxygenated (âˆ†[HbO2]) and deoxygenated (âˆ†[HHb]) hemoglobin were measured to capture neural changes. Repeated measures ANOVAs (CRF Ã— Age Ã— Stroop conditions) were performed to test the null hypothesis of an absence of interaction between CRF, Age and executive performance. Results: We also found an interaction between CRF and age on reaction times (p = .001), in which higher fitness levels were related to faster reaction times in the 61â€“69 year olds but not in the 55â€“60 year olds. Regarding Î”HHb, the ANOVA revealed a main effect of CRF in the right PFC (p = .04), in which higher-fit participants had a greater Î”[HHb] than the lower-fit (d = 1.5). We also found fitness by age interaction for Î”[HHb] in the right PFC (p = .04). Conclusion: Our results support the positive association of CRF on cerebral oxygenation and Stroop performance in healthy older males. They indicated that high-fit individuals performed better in the 61â€“69 year olds group, but not in the 55â€“60 years old group. We also observed a greater PFC oxygenation change (as measured by Î”[HHb]) in the high-fit individuals.