Abstract: An illuminating coaster assembly for removable attachment to an essentially flat bottomed, transparent beverage container to highlight a selected drink, particularly for use in a dark room or bar. The assembly comprises a generally circular housing having an opaque bottom wall, an opaque peripheral side wall, and an essentially planar, light transmitting top wall. The light transmitting top wall concentrically mounts an opaque center member spaced inwardly from the peripheral side wall, and an adhesive layer overlying at least a portion of the center member for removably securing the coaster assembly to the beverage container. To effect illumination of the assembly, the housing contains a chemical illuminating material that is activated by mixing through vigorous shaking.