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 protein/day and 11.6 mg lipid/day. 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.