A detailed survey of the nesting by green turtles (Chelonia mydas) on Ascension Island (7 o 57' S, 14 o 22' W) was conducted between 1 December 1998 and 1 October 1999. During this period there was a total estimate of 36,036 marine turtle nesting activities, resulting in the deposition of an estimated 13,881 clutches (95% confidence limits 13,092-14,660). These data suggest that 2-3 times more turtles nested than when previous detailed surveys were undertaken in the 1970's. The peak of nesting was in March, with 95% of nesting activity being recorded between 4 January and 18 May. Possible reasons for the evolution of the seasonality of nesting are discussed. Individual beaches varied greatly in density of nesting activities (range=534-10,001 activities/km; mean=6204 activities/km), density of nests (range=213-5200 nests/km; mean=2390 nests/km) and the proportion of nesting activities resulting in nests (nesting success; range=0.13-0.52; mean=0.39).