Six compounds in one fraction of seaweed Gracilaria coronopifolia (Red algae) that have radicalscavenging activity have been identified. Extraction of those compounds was carried out by maceration method using 96% ethanol. Separation and purification of the fraction were performed by liquid-liquid partition and column chromatographic methods. The obtained fractions were treated with 2,2-diphenyl-1- picrylhydrazyl and found that their radical-scavenging activities of the first (A) and the second (B) fractions from the column with a 60 min retention time were 83.12% and 90.72%, respectively. The compounds contained in the A and B fractions identified by GC-MS were 1-nonadecene; hexadecanoic acid or palmitic acid; octadec-9-enoic acid; cholesta-4,6-dien-3β-ol; cholest-5-en-3β-ol or cholesterol; and cholest-4-en-3- one. These compounds could be expected to have radical scavenging activities.