Depressive symptoms are common in older adults. Previous studies have shown that aerobic exercise is effective in treating depression and improves brain function. The goal of the current study was to determine the interrelationships between aerobic exercise, default mode network (DMN) functional connectivity, and depressive symptoms in thirty-eight healthy older adults. Results showed that (a) increased connectivity within the DMN and to the sgACC is associated with greater depressive symptoms at baseline, (b) decreases in functional connectivity within the DMN after a 12 week exercise intervention were greater for participants in the aerobic group relative to the control group, and (c) there is a positive association between changes in DMN functional connectivity and changes in depressive symptoms, but a negative association between other regions of the brain. These findings suggest that changes in resting-state functional connectivity are associated with changes in depressive symptoms in older adults with subthreshold depressive symptoms.