In recent years, the synthesis of nanoparticles via biological processes has attracted considerable attention. The use of plants and plant extracts is one of the most preferred methods for biological synthesis due to their rich biologically active metabolites. In this study, silver nanoparticles (Ag NPs) were synthesized using reishi mushroom (Ganoderma lucidum) extract. Different analytical techniques including X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis spectroscopy, and Fourier Transform Infrared Spectrophotometer (FTIR) were used for the characterization of Ag NPs. UV-vis spectrum exhibited a broad absorption peak between 400-460 nm which indicates the existence of Ag NPs. TEM images showed Ag NPs are spherical with a diameter range of 15-22 nm. In addition, it is shown that Ag NPs form a face-centered cubic structure according to XRD characterization technique. The antioxidant activity towards to 1-Diphenyl-2-picrylhydrazyl (DPPH) was also studied. The highest DPPH scavenging percentage was recorded as 76.45% at 250 mg/L. The DNA cleavage activity results indicated that the green Ag NPs caused single strain DNA cleavage activity for 30 and 60 min at 50 and 100 mg/L, respectively. The Ag NPs antimicrobial activity was also investigated and results recorded as minimum inhibition concentration (MIC). Ag NPs showed a strong antibacterial effect against gram-positive (S. aureus, E. hirae, B. cereus) and gram-negative (E. coli, P. aeruginosa, L. pneumophila subsp. Pneumophila) bacteria. Furthermore, Ag NPs have also been shown to have a high antifungal effect against C. albicans fungus. (C) 2019 Elsevier B.V. All rights reserved.