The benefit and ethics of keeping marine mammals in captivity has been a source of debate for several decades. One of the center pieces of the debate is whether there is real benefit to marine mammals as a whole that results from research on captive marine mammals. The Navy Marine Mammal Program (MMP) keeps marine mammals for national defense purposes. However, in nearly 50 years of existence, the MMP has also been a leader in marine mammal research. The results of the research conducted by the MMP has not only benefited the care of marine mammals in captivity, but has directly and indirectly improved our understanding of the behavior, physiology, and ecology ofanimals in the wild. Research conducted with the MMP marine mammal population has produced demonstrable improvements in veterinary care and has lead to some of the earliest advances inproviding guidelines for mitigating the impact of sound on wild marine mammals. Additionally, our understanding of echolocation, diving physiology, and husbandry behaviors has greatly benefited from MMP research. Future and current work conducted by the MMP will continue to add to the knowledge base of marine mammal biology while contributing to their care and conservation.