Water, nutrient and energy contents in the developing eggs and hatchlings of the green turtle Chelonia mydas were monitored during 66 day of incubation period in a beach hatchery at Saurashtra coast (northwest coast of India). The egg imported water from the surrounding medium in addition to utilization of 24.1 g water from the yolk and albumen. The developing embryo utilized 27 mg proteinlday and 11.6 mg lipidlday. On an average, each developing egg spent 86.7 kJ for embryonic development. Protein, lipid and carbohydrate contributed 48.5%, 35.2% and 16%, respectively to the energy expenditure. The energy conversion efficiency of the egg was 75%. Nearly 68% of growth was in the last 21 days, when 58% of yolk energy was utilized. At emergence, the mean dry weight of hatchlings and residual yolk were 5.8 g and 0.9 g, respectively. The hatchling reserved 11.3% of the initial dry weight as well as energy content of the yolk as residual yolk.