To investigate the association between age-related changes in risk taking and resting-state functional activity, we recorded resting-state scans from both young (n=26) and older adults (n=27). In addition, all participants completed two decision-making tasks: the Cambridge Gambling Task and the Balloon Analogue Risk Task. We found that older adults showed decreased functional connectivity within the medial prefrontal cortex, particularly between the ventromedial prefrontal cortex and the dorsal medial prefrontal cortex. Moreover, these changes in resting-state functional connectivity were associated with the individuals' risk-taking behavior, and mediated the influence of age on risk taking.