Biochemical composition of brown alga Sargassum horneri was investigated by determination of moisture, protein, carbohydrate, ash, simple lipids and glycolipids. Fatty acid composition of simple lipids and glycolipids was determined by gas chromatography. The algal specimens were collected in two different months, January (sample-1) and February (sample-2). Moisture contents were 86.94 and 87.00% in sample-1 and sample-2, respectively. Protein, carbohydrate and ash contents were 22.94, 19.93 and 32.00% of the dry sample-1, respectively, while the contents of the dry sample-2 were 21.96, 20.81 and 33.58%, respectively. Glycolipids were 1.38 and 1.96% of the dry sample-1 and sample-2, respectively, whereas 2.45 and 2.75% when the samples were digested with the abalone Haliotis discus enzyme. Of the glycolipids obtained, MGDG, DGDG and SQDG were nearly 15, 15 and 68%, respectively. The major fatty acids in simple lipids were 16:0, 18:1 and 22:0. The major fatty acids in individual lipid class were 16:0, 18:1, 20:1, 20:4 and 20:5 in MGDG, 16:0, 20:0, 20:4 and 20:5 in DGDG and 16:0, 18:0, 18:1, 18:2 and 20:4 in SQDG. S. horneri is a potential source of valuable glycolipids.