Objective: To investigate the chemical components and biological activities of avocado seed extract and fractions in order to determine the nutritional and pharmaceutical values of avocado seed. Methods: Various organic solvents were applied for extraction and fractionation of avocado seed. 1,1-diphenyl-2-picryl-hydrazyl, 2,2-azinobis-3-ethyl benzothiazoline-6-sulfonic acid, and DNA oxidation assays were applied for investigation of free radical scavenging activity. Nitric oxide production was measured by Griess reaction assay. Moreover, MTT assay was used to measure cancer cell growth inhibition. Results: The result indicated that the avocado seed contains (7.14 ± 0.40) g lipid/100 g, (1.67 ± 0.03) g protein/100 g, (54.0 ± 1.2) g carbohydrate/100 g, and (62.0 ± 2.3) mg gallic acid equivalent/g dried weight extract. Moreover, dichloromethane and ethyl acetate were revealed to be the highest free radical scavenging fractions with IC