Hydrophobic silver nanoparticles have been carried out by use of ascorbic acid in cyclohexylamine and aqueous medium. Nanosilver can be effectively coated with oleic acid and possesses oil-soluble property. Oleic acid as an extractant is also effective at stabilizing particles of similar size in an oil phase when the AgNO3 is reduced in a coexisting aqueous phase. Stable spherical silver nanoparticles 15~25 nm in diameter with a well-crystallized structure were obtained at 120 °C. The thermal stability of surface-coated silver prepared in cyclohexylamine solution was monitored by UV-vis spectral analysis.