A review on the biosynthesis of silver nanoparticles (Ag NPs) and their biocidal properties discusses the synthesis methods, including chemical, physical, and biological approaches, with a focus on green synthesis using plant extracts, fungi, and bacteria. Ag NPs are effective against a wide range of bacteria and fungi, including Gram-positive and Gram-negative bacteria, and have been used in agriculture, medicine, and food packaging to prevent microbial contamination. Their biocidal properties are attributed to the release of Ag⁺ ions, which interact with biomolecules in microbial cells, leading to cell death. Ag NPs are smaller than microorganisms, allowing them to penetrate cell walls and disrupt cellular functions. The toxicity of Ag NPs depends on factors such as size, concentration, pH, and exposure time. Green synthesis methods are preferred due to their eco-friendly nature, cost-effectiveness, and scalability. Ag NPs synthesized from plant, fungal, and bacterial sources have shown significant antimicrobial activity, with smaller nanoparticles being more toxic. However, the long-term effects of Ag NPs, including their potential to induce resistance in bacteria and their cytotoxicity to human cells, require further investigation. The mechanism of antibacterial activity involves the release of Ag⁺ ions, which interact with microbial cell membranes, leading to cell death. Ag NPs have also been shown to have antioxidant properties and can be used in biomedical applications. Despite their benefits, the use of Ag NPs must be carefully managed to avoid environmental and health risks.A review on the biosynthesis of silver nanoparticles (Ag NPs) and their biocidal properties discusses the synthesis methods, including chemical, physical, and biological approaches, with a focus on green synthesis using plant extracts, fungi, and bacteria. Ag NPs are effective against a wide range of bacteria and fungi, including Gram-positive and Gram-negative bacteria, and have been used in agriculture, medicine, and food packaging to prevent microbial contamination. Their biocidal properties are attributed to the release of Ag⁺ ions, which interact with biomolecules in microbial cells, leading to cell death. Ag NPs are smaller than microorganisms, allowing them to penetrate cell walls and disrupt cellular functions. The toxicity of Ag NPs depends on factors such as size, concentration, pH, and exposure time. Green synthesis methods are preferred due to their eco-friendly nature, cost-effectiveness, and scalability. Ag NPs synthesized from plant, fungal, and bacterial sources have shown significant antimicrobial activity, with smaller nanoparticles being more toxic. However, the long-term effects of Ag NPs, including their potential to induce resistance in bacteria and their cytotoxicity to human cells, require further investigation. The mechanism of antibacterial activity involves the release of Ag⁺ ions, which interact with microbial cell membranes, leading to cell death. Ag NPs have also been shown to have antioxidant properties and can be used in biomedical applications. Despite their benefits, the use of Ag NPs must be carefully managed to avoid environmental and health risks.