In an attempt to identify critical health issues affecting the survival of endangered leatherback sea turtles (Dermochelys coriacea), a prospective study was conducted in several dead-in-nest hatchlings and captive posthatchlings to examine pathologic changes and presence of pathogenic microorganisms. Numerous histopathologic changes were identified. Although bacterial etiologies were suspected in deaths of captive individuals, a single causative organism was not identified but rather, a mixed population of bacterial flora was cultured. Muscle degeneration observed in most samples implicates a potential environmental factor in species survival and needs future investigation.