In this work, the performance of polyester (P)/glass fiber mats (G) and P/G/calcium carbonate (CaCO3) composites was compared with that of P/G/fiberglass waste composites. The residues used were conventional P/G postconsumer light resin-transfer-molding parts, obtained via knife or ball milling. Composites with up to 50 wt % reinforcement were prepared by hot compression molding and characterized via physical (density and water sorption), thermal (thermogravimetry and burnout), and mechanical (impact, Barcol hardness, and tensile) testing. The results show that the simple grinding and reincorporation of the composite residues yielded new composites with generally worse characteristics than the ones with calcium carbonate. Then, the waste was sorted by removing most of the pure resin particles from it. This yielded a resin-rich fraction, which could be better used for energy recovery and resin-covered fibers. The use of the latter as a filler yielded composites with better overall properties than those with calcium carbonate for a controlled amount of W; thus showing potential use as a replacement for the commonly used inorganic filler, maintaining the mechanical properties, decreasing the raw material cost, and reducing the amount of composite waste discarded in the environment. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012