The aim of this study was to determine content of primary and secondary metabolites and evaluates the antioxidant activity of methanol extracts of dried ascocarps from two species of truffles, Terfezia claveryi and Tirmania nivea which were harvested in Chellala-El Bayadh- Algerian desert. Quantitative determination of sugars, proteins and lipids shows that T. claveryi was very rich in these compounds with levels of 06.04±0.46; 12.87±0.09; 03.95 ± 0.543 g/100 g DM respectively. However, T. nivea present lower rates for the same respective compounds of 5.01±0.09; 11.97±0.03 and 2.15±0.093 g/100 g DM, respectively. The extraction of total polyphenols was made by steeping in methanol. The results showed the richness of both species in polyphenols ranging between 15.4±0.11 mg EAG/g for T. claveryi and 19.74±0.69 mg EAG/g for T. nivea. The contents of flavonoids and tannins were respectively 12.03±0.27 to 12.07±0.79 mg EC/g and 2.3±0.27 to 8.28±0.02 mg EQ/g. T. claveryi and T. nivea extracts exhibit a comparable inhibitory concentrations of DPPH radical (IC50), respectively 1.02±0.002 and 1.01±0.002 mg/ml but remained significantly below (P <0.05) that of ascorbic acid (0.08±0.002 mg/ml). As well our truffles were rich in Vit.C and carotenoids. These show that the area factor affects the biochemical composition of truffles, even if they belong to different species. They keep biochemical and antioxidant characteristics nearly identical.