The need for marine finfish aquaculture to complement wild capture fisheries is becoming more apparent as the United States continues to rely primarily on imports to meet its seafood demands. However, similarly to land based aquaculture facilities disease outbreaks can be a limiting factor to industry when fish are raised under intensive culture conditions. In marine cage culture, fish are exposed constantly to ubiquitous pathogens and fish stocked from land-based hatcheries may be considered immunoincompetent to them. Under natural conditions, these ubiquitous pathogens in their natural hosts may not be considered important pathogens, however, the stress associated with captive rearing creates opportunities for disease leading to possible morbidity, mortality and economic loss in cultured fish. This lecture will focus on some of the more important diseases that could infect finfish species that are being considered for potential expansion of US marine aquaculture.