The methanolic extract of a marine red alga Centroceras clavulatum (C. Ag.) Mont., collected from the coast of Karachi, was studied for its fatty acid and sterol compositions. The analysis of fatty acid methyl esters by GC-MS revealed the presence of methyl laurate, tridecylate, myristate, pentadecylate, palmitate, margarate, nonadecylate, arachidate, behenate, tricosanoate and pentacoeanoate among saturated and methyl palmitoleate and heptadecylenate among unsaturated acids. The sterol composition divulged the presence of 22-dehydrocholeaterol, cholesterol, 24-methyl-cholesterol and beta-sitosterol, identified through main spectrometry and 1H-NMR spectroscopy.