This study deals with microwave properties of glass foams prepared from glass industrial waste. Two types of cullets (one from soda-lime silicate glasses and the other from cathodic ray tubes - CRT) have been combined with different foaming agents (C, SiC, AlN). Glass foams electromagnetic properties are primarily determined by their apparent density as well as by the nature of the foaming agent. Foams, blown with carbon as foaming agent, present high dielectric loss and could be used as green electromagnetic absorbent in building industry. (C) 2014 Elsevier Ltd. All rights reserved.