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In the present paper, the modelling and control of a visual servoing system is presented. The main different approaches to face this visual servoing problem are presented. Among them, the position-based approach is chosen. In this approach, the features extracted from the images are used to estimate the relative object-camera position. This position is then compared with a desired relative position (used as a reference for the servoing system). The preliminary calibration procedures needed for this approach are also outlined in the paper. As a first approximation to our visual servoing implementation, the planar case is considered in simulation and real experiments. In the general case, the six degrees of freedom (DOF), necessary to reach any position and orientation inside the robot work ing space, are involved. The extension to this general case is also presented, but no experi mental results have been obtained yet. The robot manipulator used in our implementation is the PUMA 560. Unlike other authors, the control commands given to this robot are not exercised directly on the joint's servomotors. Instead, the robot is commanded at a higher level, using the ALTE