The mechanical and thermal properties of hollow glass powder reinforced epoxy resin composites have previously been measured and evaluated in earlier studies (Ku et al., J Compos Mater, submitted). These basic, but critical data sets have yielded interest in relevant industries in Australia. This study therefore focused on measuring and evaluating the dielectric properties of these composites with a view to benefit these relevant industries. The relationship between the dielectric and thermal properties was also studied and correlated. The original contributions of this article states that samples postcured in an oven were found to have lower electrical as well as mechanical loss tangent values than their counterparts cured in ambient conditions alone. The storage modulus of all samples conventionally postcured was also higher than their counterparts. The conventionally postcured samples were also found to have lower glass transition temperature than their rivals and softer material. For all percentages by weight of glass powder, the glass transition temperature for the oven cured samples was higher and it can be argued that the composite was stiffer; the opposite was true for the ambient cured sample. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 2945-2952, 2011