Chemical composition in 47 samples of marine green seaweeds consisting of 9 genera [Boodlea, Bryopsis, Caulerpa, Chaemodoris, Cladophora, Codium, Enteromorpha, Udotea and Ulva] representing 27 different spp. at the Indian coast of Saurashtra region were studied. Ash, insoluble ash, sulfate, Ca, Mg, Na and K were estimated. Significant variations were observed in chemical composition among the different genera of seaweeds. The same species collected from different localities at a different period also showed considerable variations.