Compared to other movement disorders, such as Parkinson Disease (PD), the mechanisms of movement impairment in Amyotrophic Lateral Sclerosis (ALS) have not been a focus of great interest. It is at least partly related to the classical assumption that impairment of movement in ALS simply reflects a dysfunction of the final motor pathways. However, the concept that ALS purely involves upper and lower motor neuron has been definitively challenged. Accumulating evidence for the concept that ALS is a multisystem degenerative disease is supported by histological, neurophysiological and neuroimaging studies. Clinically, lower limb stiffness is associated with extrapyramidal rigidity and postural instability in 69% of ALS patients. These latter may also display abnormalities of movement initiation impairing walking, such as gait initiation failure, usually reported in PD patients. All these data support the hypothesis that some balance troubles in ALS patients may result from an additional dysfunction and/or lesion of the basal ganglia circuitry and/or of its output structures, such as the cortex or the midbrain.