Endoscopy means “to look inside” and in medical practice refers to the use of equipment specifically designed to create and transmit images of patient anatomy normally inaccessible to the unaided eye of the care provider. The wide array of modern flexible endoscopes allows inspection of virtually any portion of the body via an opening to the surface. Flexible scopes are sometimes useful in minimally invasive surgery (MIS) procedures by introduction of the scope insertion tube through small, carefully placed incisions; however, in general, MIS is the primary purview of rigid endoscopy. Flexible and rigid endoscopy are important tools for the marine mammal veterinarian. Since the publication of the previous edition of this chapter, there have been multiple cases presented in abstracts, proceedings, or publications describing the use and benefit of endoscopy in marine mammal care. Notably, two abstracts describe attempts to refine and improve the use of laparoscopy in bottlenose dolphins (Tursiops truncatus; Dold et al. 2012; Coisman et al. 2013), and a review paper of surgical procedures in pinnipeds and cetaceans includes a discussion of MIS (Higgins and Hendrickson 2013).