After describing the state of the art concerning the knowledge of the rotations of the asteroids, obtained from observational data, we show how it was possible to compute with very high accuracy the ephemerides of the rotational motion of the asteroid Eros 433, starting from the informations given by the NEAR (Near Earth Asteroid rendezvous) probe. We separate the motion into two components, the free and the forced motions, which are analysed separately, then mixed together.