This paper evaluated antioxidant, antimicrobial and antibiofilm activities of ethanol, methanol, acetone and chloroform extracts of lignicolous fungal species Fomes fomentarius (L.) Fr. (Polypodiaceae). Antiradical activity was evaluated by using DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. The antimicrobial screening was carried out via disc diffusion-method in order to estimate minimum inhibition (MIC) and minimum bactericidal concentration (MBC) of analyzed extracts against seven standard bacteria and one yeast: Escherichia coli NRRL B-3704, Pseudomonas aeruginosa ATCC 27853, Proteus vulgaris ATCC 13315, Acinetobacter baumanii ATCC 19606, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, S. haemolyticus ATCC 43252 and Candida albicans ATCC 10231. In vitro antibiofilm activities were investigated based on crystal violet binding assay. All the extracts showed higher antioxidant activity compared to BHT (butylated hydroxytoluene) which was used as a standard. Ethanol, methanol and acetone extracts of the tested macrofungus also showed higher antimicrobial effect against P. aeruginosa ATCC 27853 in comparison to the antibiotic penicillin (P10). The lowest MIC was recorded by ethanol extract against S. haemolyticus ATCC 43252 (0.625 µg/mL). The highest antibiofilm activity was also noticed against biofilm formed by S. haemolyticus ATCC 43252. The results indicated that the F. fomentarius tested represent potential source of natural bioactive compounds with respect to antimicrobial, antibiofilm and antioxidant activities.