The invention relates to an automated registration method and device for a surgical robot, allowing registration between a first three-dimensional positioning system which comprises an optical distance sensor, and a second three-dimensional positioning system which comprises optical acquisition means. The method comprises: - a first step in which pre-operative registration is carried out between the first positioning system and recorded data relating to an anatomical surface of a patient, and - a second step of pre-operative registration for the two three-dimensional positioning systems. The second registration step takes place concurrently with the first registration step, by detecting, using said optical acquisition means, at least one point in a cluster of points acquired by the optical sensor during the first pre-operative registration step.
