This paper presents the development of an electric thruster for inspection class underwater Remote Operated Vehicles (ROVs). The general aspects of brushless motors are covered. The technical requirements defined for the thruster are presented. The chosen motor and its drive system, which is divided in power circuit and control circuit, are described. The power circuit topology is presented, where special attention is given to the power switches driving method and to their power losses. Experiments conducted in a hyperbaric chamber, load and thrust tests are described and the results obtained with them are presented. It is concluded that the developed prototype meets the established requirements.