Abstract: The Phoenix dactylifera (date palm) is one of the member of the genus Phoenix, widely cultivated for its edible fruit. Date seeds, considered as waste product, are either discarded or used as fodder for domestic farm animals and potentiality to use as source of antioxidant and biodiesel production. Methanolic extract of four cultivars of date seeds (Haiany, Ramly, Sewy and Amhat) showed pronounced antioxidant activity against 2, 2 diphenyl-1-picrylhydrazyl (DPPH) method ranged between 93.53% (in Haiany) and 88.37% (in Amhat) compared to the natural antioxidant vitamin C (91.45%) and the same trends were observed with 2,2'- azino-bis (ethylbenzthiazoline-6-sulfonic acid (ABTS•+). The antioxidant substances (total phenolic compounds and total carotenoids) as well as oil contents (%) were determined in the date seed cultivars under investigation. Transesterification of the date seed oils (ranged 4.48 and 3.31%) and the characteristics of the produced biodiesel were performed as; color, iodine value, acid value, saponification value, higher heating value and cetane number. The date seed oils were analyzed using gas chromatography for their fatty acid composition. Saturated fatty acids (C8:0 to C18:0 and C20:0) represent the highest percentage in Amhat (79.517%) and Haiany (68.135%), while Ramly has the least saturated fatty acid content (20.986%). Oleic (C18:1) and linoleic (C18:2) acids represent the only unsaturated fatty acids in date seed oils. The highest percentage was recorded in Ramly cultivar (20.99% of oleic acid+3.65% of linoleic acid) while the other cultivars have very low relative contents (0.093-3.65%). Infrared spectrum of the methyl ester of date seed oil showed the absence of hydroxyl peak which can be correlated to the transesterification process, in addition to the presence of the ester groups at bands, 1745, 1165, 1107 nm. From the results it was clear that, there are strong potential for date seed oil to be used as a source of biodiesel, as well as in pharmaceutical applications as new sources for antioxidant substances (Phenolic and Carotenoids).