Wet weight, dry weight, water content, ash weight, soluble and insoluble proteins, carbohydrates, lipids, and glycogen were determined from 0 to 40th day after fertilization of the developing eggs of the Indian horseshoe crab, Tachypleus gigas. The water and ash content increased steadily from 34.12 to 81.35% and 6.35 to 12.00% respectively from 0 to 40th day after fertilization. Dry weight of the developing eggs decreased with increase in the stages of development. The protein values increased from 7.02 to 11.53 mg/100 mg; insoluble protein fraction decreased rapidly from 43.15 to 26.01 mg/100 mg with the development of the eggs. The carbohydrate content decreased from 10.65 to 4.53 mg/100 mg. Similarly, the lipid content decreased relatively and varied from 33.15 to 27.35 mg/100 only in the later stages of development. The glycogen decreased considerably from 3.07 to 0.09 mg/100 mg.