Age-related brain changes are the main cause of cognitive decline. Active cognitive task performance as well as resting-state activity might be a sensitive index for studying differences in aging. We investigated age-related changes in the spontaneous neuronal activity with functional magnetic resonance imaging (fMRI) in a resting-state condition. To evaluate differences in aging, we analyzed functional connectivity between resting-state networks in two groups of older and younger healthy volunteers. Seven resting-state networks were isolated, and cross-correlation matrices were computed for the time courses. Older subjects showed decreased activity of the auditory, visual, sensory-motor networks, frontoparietal and salience networks accompanied by increased coupling of the salience network with the sensorimotor and default mode network compared to younger subjects. The age-related differences in functional connectivity may be due to aging impairment of the prefrontal cortex leading to a loss of activation in the salience, sensorimotor and visual networks in older subjects compared to the younger subjects. However, the default mode network was more prominent in the left hemisphere and showed more coupling with the salience network in older subjects than in younger subjects, indicating possible compensatory engagement of cognitive control regions in resting-state cognition. The results show that independent of task design and performance the functional connectivity method reflects neural changes in the aging brain.