This research was aimed to determine nutritional values and antioxidant activity of wild edible mushrooms from northern region of Thailand as well as effect of processing on their chemical compositions and antioxidant activity to extend the shelf life of wild mushroom. Seven wild edible mushrooms namely Hed Lom Kaw (Russula delica Fr.), Hed Kone (Termitomyces sp.), Hed Kai Han Kaw (Amanita princeps Corner et Bas.), Hed Kai Leung (Amanita calyptroderma Ark. et Bal.), Hed Daeng (Russula lepida Fr.), Hed Har (Phaeogyroporus braunii [Bres.] Sing.) and Hed Phor (Astreaus sp.) were used in the study. Fresh mushrooms had moisture content in the range of 80.30-93.96% fresh weight. Nutritional values of wild edible mushrooms in terms of carbohydrate, crude protein, crude fat, crude fiber and ash were in the range of 49.50-59.74, 18.35-27.57, 1.47-5.85, 4.19-12.90 and 4.03-10.74% dry weight, respectively. Hed Lom Kaw provides a highest amount of carbohydrate (59.74% dry weight) as well as Hed Har provides highest amount of protein (27.57% dry weight). Four major minerals in mushrooms such as Iron, calcium, potassium and phosphorus were in the range of 3.43-15.35, 16.83-85.84, 577.32-3,169.50 and 144.63-701.25 mg/100 g dry weight, respectively. Total phenolics content of the mushrooms were in the range of 6.14-20.63 mg GAE/g dry weight. Hed Phor and Hed Har had the highest content of total phenolics. The most abundance amino acid contents in all mushrooms were Glutamic acid (2.82-43.64 mg/g dry weight) and Aspatic acid (3.25-19.57 mg/g dry weight). Limiting amino acids in several mushrooms were Cysteine Methionine and Lysine. All mushrooms in this study had Amino Acid Score (AAS) lower than 100. Protein quality of wild edible mushrooms was incomplete protein. Antioxidant activity of methanol extractions from wild edible mushrooms was reported in term of EC₅₀ values. The EC₅₀ values of DPPH (2,2-diphenyl-l-picrylhydrazyl) radical scavenging activity and reducing power were range in 5.00-50.00 and 11.67-55.56 mg dry weight/ml, respectively. The chelating activity on ferrous ions of all mushrooms were range in 49.03-80.27%. The AEAC (ascorbic acid equivalent capacity) and TE (trolox equivalent) values of wild edible mushrooms were range in 19.35-77.40 mg ascorbic acid/100 g dry weight and 6.52-42.23 µmol trolox/g dry weight. Wild edible mushroom had higher antioxidant activity than commercially shiitake mushroom (Lentinus edodes) (p ≤ 0.05). Drying mushrooms at 50°C for 8 h. had an impact on chemical compositions and antioxidative properties of selected mushrooms. Amino acid contents of dried mushrooms (Hed Lom Kaw, Hed Har and Hed Phor) lower than fresh mushrooms (p ≤ 0.05) as well as total phenolics content and antioxidant activity (Hed Lom Kaw and Hed Har).