Walking appears to be a simple innate ability, but it is an extraordinarily complex process involving three major afferent systems (visual, proprioception, and vestibular). Humans' unique gait is established around age seven. Velocity and step-length change with age, but the overall package we call "gait" remains stable. Age is the single most important factor in changing gait, with some normal changes expected. Gait disorders, beyond what are normal age-related changes, are common among elders. At 60 years of age, 15% of elders have gait problems, increasing to 82% for those 85 years of age and older. Abnormal gait movement can be broadly defined as hyperkinetic (too much movement) and hypokinetic (too little movement). Gait disorders are classified into lowest level (affecting one afferent system), middle level (more afferent system involvement), and highest level (characterized by planning deficits) disorders. Gait disturbances may be a manifestation of underlying conditions or may be drug-induced. To treat gait disorders appropriately, clinicians must review the patient's disease progression, medication status, and environmental conditions. Physical therapy, medication changes, and, rarely, surgery can help improve gait.