Noise acts by means of the ear on the central and autonomous nervous systems. When this stimulus passes determined limits, it provokes deafness and has pathological effects, both instantaneous and differed, on both nervous systems. At much lower levels, noise produces discomfort, diminishes attention, or impedes communication, concentration and sleep; noise reduces school or professional performance; noise increases the possibility for antisocial behavior; noise can lead to a loss in the value of a building or can cause accidents in the work place. The author describes the importance of this topic, reviews the anatomical-physiological features of the ear, and describes noise and its properties. The author also describes how noise affects our organism, habits, life styles, society, working environment and health. The author finishes by providing some current preventive measures and some recommendations to avoid this pollutant.