The ageing process is normally accompanied by several physiological changes like a decline in physical function and increased risk of chronic health conditions. In older adults, maintaining physical function and cardiovascular health is essential for maintaining independence and quality of life. Cardio-respiratory fitness and physical functional capacity (PFC) are two important indicators of physical health in older adults. This study aims to investigate the mediating effect of physical activity (PA) on the relationship between CRF and PFC in older adults. Using quantitative cross-sectional design, we employed a multistage sampling strategy to recruit 998 older adults from Navrongo for this study. The senior fitness test battery, international physical activity questionnaire (IPAQ) short form for elderly, weighing scale and tape measure were used to collect the data. The findings revealed that, 53.4% and 53.9% of these older adults had reduced PFC and CRF respectively. It was also found that PA partially mediates the relationship between CRF and PFC of the older adults with an indirect effect of CRF on PFC as β = .0030, t = 1.579 p < .05, with a direct effect of CRF on PFC, β = .867, t = 42.954, p < .05, and the total effect, β = .872, t = 43.110, p < .05. We concluded that physical activity partially mediates the relationship between CRF and PFC among older adults in Navrongo. Therefore, there is the need for evidenced-based intervention to promote PA among these older adults to improve their PFC and quality of life.