Acoustic and visual cues are frequently used in gait rehabilitation. Attuning the steps to the cues is attentionally demanding. We examined the attentional demands of walking to two types of cues using a probe reaction time (RT) task. The steps were cued by either metronome beeps or visual stepping stones projected on a treadmill. The coupling between gait and these cues was assessed using a perturbation paradigm. In view of age-related changes in attentional demands of motor control, both elderly and young adults were tested. RTs were determined for walking to the two types of cues, as well as for three control conditions, viz. uncued walking, standing, and sitting. For all conditions, RTs were higher for elderly adults. However, the difference between elderly and young adults did not vary over conditions. Uncued walking required more attention than did standing and sitting. The attentional demands were further elevated during cued walking, with larger RTs for walking to visual stepping stones than to metronome beeps. Because the coupling to the cues was superior in the stepping stones condition, this type of cues seems to aid cued walking by allocating higher levels of attention to task-relevant information (viz. future footfall positions). Hence, the observed differences between the two cueing types may be associated with the natural dependence of gait on visual information.