The advent of plastics and the wide range of fillers that are available have made modification as precise as the tailored resins themselves. Compounds are prepared from poly (methyl methacrylate) (PMMA), and two fillers, talc and synthetic sodium aluminum silicate (SSAS), at varying concentrations (up to 40wt%). The effects of both the fillers on the mechanical, thermal, and electrical properties, salt spray performance; Rheological as well as optical properties of filled PMMA are measured. The impact strength of PMMA increased with increasing concentrations of talc and SSAS up to 20 and 15% loading, respectively, and thereafter declined continuously in both the cases. Increase in impact strength is more in the case of talc-filled PMMA than that of SSAS-filled PMMA. Tensile strength decreased with increasing concentration of both the fillers continuously. The elongation at break decreased drastically for PMMA with increasing concentrations of both the fillers. Electrical properties remained almost unchanged with respect to the concentration of the fillers. The zero shear viscosity increased with increasing concentration of both the fillers, but the rate of increase was more for SSAS than that for talc. © 2005 Sage Publications.