Variations in biochemical and mineral composition of muscle, hepatopancreas and ovary were studied during ovarian maturation in the spiny lobster, Panulirus homarus. Among the organic reserves in the muscle, lipid alone showed a decline during maturation. In contrast, all the organic reserves in the hepatopancreas declined in the mature and spent lobsters. The decrease in hepatopancreatic reserves amounted to 22.92% (lipid), 0.67% (protein) and 33.33% carbohydrate) of the total of these organic materials deposited in the mature ovary. The decrease in energy reserves in hepatopancreas and the corresponding increase in the mature ovary indicates that hepatopancreas is the main source of glycolipoproteins contributing to the vitellogenic processes. In the muscle, concentrations of Ca, Na, P, Mg, Cu, Zn, Mn, Co and Cd increased with attainment of maturity and declined after spawning. However, K was in maximum concentration (17.56 mg/g dry wt.) in immature and Fe (176.96 mg/g dry wt.) and Cr (18.7 mg/g dry wt.) in spent stages. Na, Ca and Mg concentrations in the hepatopancreas increased while K and P decreased in mature and spent lobsters. With the exception of Co, all the trace elements in the hepatopancreas increased with maturation; Cu (3507.33mg/g dry wt.) and Cd (61.34mg/g dry wt.) recording 10 and 17 fold increases. In the ovary, all the minerals and trace elements increased significantly (p<0.01) up to the ripe stage and decreased after spawning