Ag-109 MAS-NMR spectra of AgI-based glasses containing frozen alpha -AgI nanocrystals were measured extensively for AgI-Ag2O-MxOy (MxOy = B2O3, GeO2) systems. The spectrum of alpha -AgI frozen glass composite observed at room temperature was separated into three components, which were ascribed to glass matrix, alpha -AgI nanocrystals and crystalline beta -AgI. The temperature dependencies of the spectra suggest the formation of more alpha -AgI nanocrystals by heating.