Silver nanoparticles have been extensively researched and have several applications such as antimicrobial and anticancer, and can be used in the agricultural, biomedical, pharmaceutical, textile area, among others, but its toxicity is still little understood. Nanoparticles can measure between 1 – 100 nm and the most currently studied is the silver nanoparticle (AgNP). The main methods of synthesis are the chemical and the biogenic pathway, or green, which is less environmentally polluting, more environmentally friendly, and simpler, although standardization is more complex. Morphological and physical-chemical characteristics differ according to the synthesis method and, consequently, present different degrees of toxicity. Nanotoxicology studies the toxicity of nanoparticles on living organisms and scientists seek to know about the physical-chemical properties and their influence on interaction with the environment. It is known that there are several parameters that influence toxicity, such as dose, particle size, shape, morphology, surface chemistry, agglomeration/aggregation state, synthesis method, cell type and organism in which it is tested. Therefore, this article aims to address the main ways of synthesis of AgNPs, discuss the advantages and disadvantages of each method, the parameters that influence toxicity and examples of studies.