Adult mortality at the nesting site is an important demographic parameter for green turtles (Chelonia mydas) at Aldabra Atoll, Seychelles, where, between 1995 and 2008, records were kept of adult green turtles found dead (n  =  158) or so trapped or incapacitated in the vicinity of the nesting beaches as to be unable to return to the sea without human assistance (n  =  50). The main cause of death (n  =  121) was entrapment and/or incapacitation on beach rock (62.0%), and adjusted rates of mortality were twice as high on the windward south coast as on the north coast and 3 times that on the west coast. Annual natural mortality, conservatively reported at 16–30 females per year, claims an estimated 0.3%–1.0% of the annual adult female nesting population at Aldabra, which is otherwise healthy, increasing, and free of terrestrial predation.