Despite the growing magnitude of shellfish aquaculture in a worldwide context, explicit study on crab endocrinology in terms of growth and reproduction is lagging behind. It is necessary to modify the methods of crab culture to increase food production for forever growing human population. The crab O.senex senex, selected as a test animal due to its year-round availability, well known physiology and is edible known as "poor man's protein". Eyestalk, a major endocrine centre liable for synthesis and release of CHH-family peptides and are isolated from several crustacean species, but not much from crabs. Hence the present work mainly concerns with the isolation and characterization of eyestalk peptide hormones involved in directive of molt and reproduction along the natural molt and reproductive cycles in crab. Besides this, cloning of eyestalk peptides was performed in crab O.senex senex and prawn M.rosenbergii. This book presents a humble effort by the author towards a better indulgent of the eyestalk peptide hormones on the regulation of molt and reproduction in crab and it provides a basis for further studies to promote growth and reproduction in edible crustacean species.