Due to the unique antimicrobial properties, silver is widely used in commercial products. Silver nanoparticles (AgNPs) with much stronger bactericidal potential than silver itself have been used in a much broader range. However, the biosafety of AgNPs has not been totally evaluated yet. Dendritic cells (DCs) residing in almost all tissues are the most potent antigen-presenting cells (APCs). Since AgNPs have been widely investigated in areas of antibacterial applications as well as drug delivery and targeting, it is quite helpful to study the effects of AgNPs on DCs which are able to orchestrate both innate and adaptive immune responses. DCs were derived from human peripheral blood monocytes. First, we found that the addition of AgNPs promoted the proliferation of DCs. Then, we found that the effects of AgNPs on DC maturation were very complex. Low concentration of AgNPs slightly promoted DC maturation mediated by LPS according to the expression of some key markers. However, the higher concentration of AgNPs showed some inhibition to LPS-mediated DC maturation. We tried to investigate different AgNPs with various coatings. Further study on the mechanism of AgNPs affecting DC maturation is underway.