In this paper, the design of the overall architecture and the development of specific components of a supervised, automatic system for guidance of an ROV are described. Basically, automation is achieved by inserting a PC, equipped with A/D-D/A boards, in the operator/ROV loop. In this way, the original configuration of the ROV manual guidance system is substituted by a more versatile, user-friendly and powerful PC-based configuration. The paper describes the basic features of the realized system, that, by allowing both on-line processing of sensory data and implementation of control procedures, enhances the performances of the ROV as a robotic tool.