This paper describes a real-time eye-gaze tracking system that bases its accuracy in a very precise estimation of the user's pupil centre. The system consists of two cameras, four illuminators and a low cost cluster of four PC's interconnected by a gigabit network. One of the cameras is mounted on a pan-tilt unit in order to perform the tracking of the person's eye. The second camera is fixed, gets a general view of the scene and it is used for finding the eye when the first camera loses it. Since high precision is needed for the determination of the point of gaze, high resolution images must be processed, For fulfilling time restrictions, image processing must be parallelised.