The lipid profile was determined in selected ecotypes of Cactus pear (Opuntia ficus indica), and this research focused on the antioxidant properties of seeds from Cactus pear fruits. Using the methodology of methyl esters the composition of fatty acids of seeds was determined and in the case of antioxidant properties the known technique of Trolox Equivalent Antioxidant Capacity (TEAC) was used. The trolox evaluation assay was applied in aqueous - organic extracts and their residues. The seed oil composition of cactus pear fruits was studied at harvest time. Linoleic acid (70.03%) was the dominant fatty acid, followed by oleic acid (20.11%) and palmitic acid (11.86%), respectively. Among cactus pear seeds, polyphenols contribution to antioxidant properties ranged from 37.9% to 42% for TEAC values. According to the results, the seeds of Cactus pear are a good source of useful lipids and antioxidants.