After discussing the basic principles of the side-scan sonar method, the author examines the sonar's advantages and applications in oil prospecting and exploitation operations by the offshore industry. Included are a number of examples illustrating the use of the side-scan sonar to test the underwater pipeline's continuity and location, the production platforms, to help position drilling rigs, and as an aid in the delineation and mapping of the seafloor during the marine exploration for oil.