Wild medicinal mushrooms have been considered as therapeutic agents since long in Asian countries, but their use in Tunisia has been slightly increased only since the last few years. This study is, to our knowledge, the first to investigate the richness of four wild Tunisian edible and medicinal species of basidiomycetes (Tricholoma terreum, Tricholoma equestre, Ganoderma lucidum and Agaricus campestris) on phenolics, fatty acids and to evaluate their antioxidant properties via 5 in vitro tests. Significant differences were observed in phenolic contents and antioxidant capacities between species. G. Lucidum extract exhibited the highest phenolic and flavonoid contents (18.7 mg EAG/g DW and 5.3 mg CE/g DW) related to the important total antioxidant capacity (5.4 mg EAG/g DW), DPPH (IC50=0.14 mg/mL), ABTS (IC50=0.98 mg/mL) and Β-carotene bleaching tests (IC50=0.26 mg/mL), respectively. Fatty acids profiles of these species were carried out by chromatography. High levels of unsaturated fatty acids (79.5-84.2 %) were observed in all species, which gives them an important nutritional value. The dominant fatty acid was linoleic acid followed by the oleic acid. Percentage of these two compounds varied from 40% to 60.2% and 16.65% to 37.17 % respectively.