The effect of sun-drying, oven-drying, and freeze-drying methods on the nutritional composition of the seaweed Sargassum hemiphyllum (Turn.) C. Ag. was investigated. Proximate and nutrient compositions (amino acids, fatty acids, minerals, and vitamin C) of the seaweed dried by the above methods were determined. The results indicated that dietary fiber and ash were the most abundant components of seaweed S. hemiphyllum. No significant differences in the content of crude protein and crude lipid were found among all three dried seaweed samples. Freeze-dried seaweed had the highest content of total amino acids, total polyunsaturated fatty acids, and total vitamin C when compared with sun-dried and oven-dried seaweed. However, sun-dried seaweed has the lowest values of ash, mineral, and total vitamin C contents among the three dried seaweed samples. This might be due to the leaching effect and long exposure time to air during sun-drying. Although oven-dried seaweed had the greatest nutrient losses, probably due mainly to the effect of high temperature during drying, it contained the highest mineral content. Thus, it can be concluded that the nutritional composition of seaweed S. hemiphyllum is greatly affected by different drying methods. Keywords: Seaweed; freeze-drying; oven-drying; sun-drying; nutritional composition