A marine brown alga, Padina tetrastmmatica Hauck, collected from Buleji near Karachi, has been investigated phycochemically. Five saturated fatty acids, i.e. isomyristic, palmitic, margaric, stearic and arachidic, three unsaturated fatty acids, i.e. palmitoleic, oleic and tetradecatrienoic have been detected and identified by preparation of their methyl esters and GC-MS analysis. Two sterols, i.e. 24-methyl cholesterol [1] and 24-methylone cholesterol [2] have been isolated and identified by GC-MS, EI and NMR, which are being reported for the first time from the genus Padina.