The aim of this study was to assess the influence of silver nanoparticles (AgNPs) on the number and diversity of microbial community in different environments (soil extract, water, sewage), and to determine whether the environment inhibits or accelerates the influence of AgNPs on moulds. AgNPs (45 ppm) present in the environment decreased bacterial (91%) and fungal (33-85%) numbers, and eliminated some strains, e.g., Alternaria alternata and Cryptococcus laurentii. Based on the biomass growth of Aspergillus niger and Penicillium chrysogenum in a medium with AgNPs and the environmental samples, it was noticed that environment can enhance (soil extract) or inhibit (sewage) antifungal activity of AgNPs.