Ceramic floor tile production lines commonly produce two types of waste: ground fired biscuit waste of ceramic tiles (WGB) and ground glazed fired floor tiles waste (WGF). These two wastes come from the same starting alumina silicate base materials but differ in thermal treatments (further firing) and surface treatments (glazing). These waste ceramics were ground into fine powders and evaluated as potential fillers for acrylonitrile butadiene rubber (NBR). The raw ceramic powders were investigated through X-ray diffraction, X-ray fluorescence, and laser scattering techniques. Particulate composites consisting of an NBR matrix with ceramic filler contents of 5, 10, 15, 20, 30, 40, and 50% were prepared in the form of cubes and discs. Scanning electron microscopy was used to determine the filler distribution inside NBR matrix. Electrical, mechanical, and thermal properties were also investigated. The electrical permittivity epsilon ' and the dielectric loss epsilon '' were found to be higher in the case of NBR/WGB than those measured for NBR/WGF at the same filler content. The mechanical properties follow the same trend as that of the electrical properties. The thermal stability of 5 and 40% concentrations were studied and the results indicate that the WGB loaded samples showed higher thermal stability than the samples loaded with WGF. Finally, the utilization of these ground waste ceramics as fillers for NBR was recommended due to improvements in electrical insulation, antistatic behavior, and thermal stability, especially for the Biscuit waste. Note that at the 30 wt% concentration for both fillers in NBR, results in composites that fulfill the targets of economical and environmental goals. POLYM. COMPOS., 40:544-552, 2019. (c) 2017 Society of Plastics Engineers