Significant advances in veterinary diagnostic and surgical techniques have been made over the past several decades. Many of these advances, however, have not reached the field of marine mammal medicine. A number of limitations exist: risks of anesthesia, anatomical challenges, difficulties with wound closure, environmental constraints, equipment limitations, and perceived risks. Despite these limitations, surgical treatments have been successfully utilized in marine mammals. While surgery is performed in pinnipeds more frequently than in cetaceans, studies conducted in the 1960s and 1970s on dolphin sleep and hearing demonstrated that general anesthesia can be successfully induced in cetaceans. Since this pioneering work, a small number of successful surgeries have been performed in dolphins under both general anesthesia and heavy sedation. While these surgical procedures in pinnipeds and cetaceans have typically been limited to wound management, dentistry, ophthalmic procedures, fracture repair, and superficial biopsy, a number of abdominal surgeries have also been performed. Recently there have been pioneering successes in the application of minimally invasive surgery in marine mammals. Many of the anatomical challenges that almost prohibit traditional laparotomies in cetacean species and present challenges in pinnipeds can be overcome through the use of laparoscopic techniques. Due to the limited number of pinnipeds and cetaceans in captivity and, thus, the limited case load for veterinarians serving marine mammal species, it is vital for knowledge of surgical procedures to be shared among those in the field. This paper reviews case reports of surgical procedures, both traditional and laparoscopic, in pinnipeds and cetaceans. Limitations to performing surgical procedures in marine mammals are discussed and surgical case reports analyzed in an effort to determine challenges that must be overcome in order to make surgery a more feasible diagnostic and treatment option in the field of marine mammal medicine.