This chapter addresses the role of afferent feedback and reflexes in the regulation of interlimb coordination in animals and humans with a focus on locomotion. From the work on cats it is known that the rhythmic muscle activities during gait are generated by specialized neural circuits located in the spinal cord (the so-called central pattern generator, “CPGs”). These CPGs are coordinated by neurons, which interconnect both sides or which transmit information between the cervical and lumbar spine. It is argued that afferent input, especially load-related information, plays a major role in shaping the resulting coordination of these CPGs. Induced changes are seen not only with a general loading of the animal but also with the selective loading of a given limb. Such principles also apply to human locomotion. Studies on infants have shown that basic coordination patterns exist, very similar to those found in the cat. The effects of afferents (notably those related to load and to hip position) play an important role in phase transitions, much as was described in feline models. In adults, the role of proprioceptive afferents was studied by muscle vibration (selective stimulus for la afferents) and by adding load (activating mainly Ib afferents). When applied during gait, tendon vibration has little effect on intra - and interlimb coordination. In contrast, load manipulations produce more profound changes. During gait, the loading of one of the limbs induces adaptations in inter-limb coordination in the 3 remaining limbs, thereby providing rhythm constancy (stable cadence). This is in line with other evidence indicating that the coordination between arm and leg movements is quite robust across various types of locomotion, suggesting a strong coupling between both homologous and non-homologous limbs.