Processes for the production of metal nanoparticles. In one aspect, the invention is to a process comprising the steps of mixing a heated first solution comprising a base and/or a reducing agent (e.g., a non-polyol reducing agent), a polyol, and a polymer of vinyl pyrrolidone with a second solution comprising a metal precursor that is capable of being reduced to a metal by the polyol. In another aspect, the invention is to a process that includes the steps of heating a powder of a polymer of vinyl pyrrolidone; forming a first solution comprising the powder and a polyol; and mixing the first solution with a second solution comprising a metal precursor capable of being reduced to a metal by the polyol.