The effect of Ag on the crystallization behavior of rapidly solidified amorphous Zr65Al7.5Cu17.5-xNi10Agx (x=0,2.5,5,7.5,10) alloys has been studied by using differential scanning calorimetry, X-ray diffractometry, and transmission electron microscopy. The amorphous phase in Zr65Al7.5CU17.5Ni10 alloy crystallizes via coprecipitation of icosahedral phase and NiZr2 phase in the first crystallization step, followed by decomposition of the quasicrystal into CuZr2 and NiZr2 phase. The NiZr2 phase transformed to stable Zr6NiAl2 phase at high temperature. The alloys containing Ag crystallizes via a two step process: Firstly, quasicrystalline phase nucleates and grows in an amorphous matrix; Secondly, the quasicrystal and remaining amorphous transformed into a stable CuZr2 and Zr6NiAl2 phases. With increasing Ag, the icosahedral phase becomes more thermally stable and the quasicrystals grain size decreased.