Nowadays, the surveillance and inspection of underwater installations, such as power and telecommunication cables and pipelines, is carried out by trained operators who, from the surface, control a Remotely Operated Vehicle (ROV) with cameras mounted over it. This is a tedious, time-consuming and expensive task, prone to errors mainly because of loss of attention or fatigue of the operator and also due to the typical low quality of seabed images. In this study, the development of a vision system guiding an Autonomous Underwater Vehicle (AUV) able to detect and track automatically an underwater power cable laid on the seabed has been the main concern. The system has been tested using sequences from a video tape obtained by means of a ROV during several tracking sessions of various real cables. The average success rate that has been achieved is about for a frame rate higher than 25 frames/second.