This paper describes a real-time, fiber-optic downhole video (DHV) system and its use as a diagnostic tool in solving production problems in Prudhoe Bay wells. Recent developments in lens preparation technology and advancements in the application of electro-fi ber-optic cable have proved the viability of DHV surveying in oilfield applications. This paper presents case histories of the first field applications in which the fiber-optic DHV system was used to perform downhole visual inspections of tubulars and casing. These operations determined fluid entry under flowing conditions, verified tubing and casing integrity, and facilitated wireline fishing operations. The fiber-optic system provided more comprehensible identification capabilities and other operational advantages than obtainable with alternative methods of downhole diagnostic techniques or the DHV coaxial-cable systems. This paper also overviews the enhancements made since the first applications of fiber-optic cable.