Resumo. Scleroderma verrucosum is a species of mushroom belonging to the family Sclerodermataceae found in the Americas and Europe. This study aimed to evaluate the 70% ethanol extract of the vegetative part of the mushroom S. verrucosum for qualitative phytochemical constituents and total content of flavonoids and phenolics, and the DPPH free radical reduction activity. Mushroom extract was prepared in 70% ethanol solution. Qualitative phytochemical assay was performed for different groups using colorimetric reagents. The contents of total flavonoids and phenolics, and antioxidant activity in reducing the DPPH free radical were quantitatively determined. The positive presence of alkaloids, flavonoids, phenolics, triterpenoids, steroids, tannins, organic acids, reducing sugars, aromatic compounds and carboxylic acids were observed. The extract exhibited total flavonoid content = 60.14 QE 100 g-1, for total phenolics = 309.14 GAE 100 g-1 and free radical reduction of = 5.97 µg mL-1. Mushroom extract Scleroderma verrucosum demonstrated the presence of several medicinal important phytochemical groups as well as total flavonoid and phenolic content that exhibit the potential for antioxidant activity.