Electroencephalography (EEG) has been extensively studied in humans over the last decades. It has been especially used in human medicine as a diagnostic tool to assess cerebral dysfunctions like for example epilepsy. EEG is especially useful to characterize different levels of vigilance from the different stages of sleep to wakefulness. Electroencephalography presents also a large interest for studies of animal brain processes from basic research on sleep, attention, awareness to applied issues such as the impact of anaesthesia, brain damages, induced or spontaneous brain diseases, epilepsy. In humans, EEG recordings are mostly based on non-traumatic external electrodes placed on the head’s skin. The quality of these human EEG recordings depends on the subject’s quietness. Of course, more difficulties are thus encountered with animals. Thus, in awake animals, it is almost impossible to avoid movements and therefore most EEG recordings in animals have been done either by means of invasive deep implanted electrodes (in the skull) requiring a surgery under anaesthesia, or by a non-invasive approach but requiring the immobilization of the animal to avoid any muscular activity and the head’s shaving in order to glue the electrodes. These methods require a relatively long preparation and can be practiced only in adapted facilities such as veterinary clinics. However, EEG is a precious tool for evaluating brain alterations or dysfunction due to diseases or trauma, but also the vigilance state of the animal, for testing the impact of drugs, welfare reasons or studies on cognition. It is then crucial to be able to use it in a field situation that is in the home environment of the horse, and preferably on free-moving animals. This tool must thus be non-invasive and furthermore not require too "visible" interventions as the shaving of the zone where electrodes are placed, as do the actual studies using an ambulatory system. Not gluing electrodes that can also induce other problems, as risking to cause a rejection of the animal after electrodes extraction. The existing systems not being thus satisfactory, a new recording system easy to use seems necessary in order to perform new researches on horses using EEG. This system must be: 1)usable in the horse home environment; 2)easy and rapid to adapt to each horse head; 3)usable on a free moving animal We developed a new EEG helmet (patent # R23701WO) adapted to the horse’s head that solves all the above mentioned issues. It allows an easy and fast (less than 5 minutes) positioning of 5 electrodes on the horse forehead. The electrodes positioning allows to record independently each brain hemisphere. The EEG amplifier developed by the company RF-Track Rennes possess an embarked memory and a Bluetooth emitter that allows to record and visualized the data in a computer in real time. This demonstration will consist in showing that this new helmet can be positioned on the horse head within 5 minutes and allows to make quality EEG recordings on a free moving horse in its usual environment. It will show that this easy to use helmet will open a field of new possibilities in cognitive sciences as well as in veterinary clinic. Take home message This EEG helmet, easy to use on free moving horses, presents a large interest for studies on animal brain processes from basic research on sleep, attention, awareness to applied issues such as the impact of anaesthesia, brain damages, induced or spontaneous brain diseases, epilepsy.