The viscoelastic properties of vinyl ester (VE) composites filled with calcium carbonate (CC) (CaCO3) powder have been evaluated using the dynamic mechanical analysis (DMA) technique. It was found that irrespective of the percentage by weight of CaCO3 powder, the VE composites postcured in an oven up to 60 degrees C have higher glass transition temperatures (T-g) and storage modulus than their counterparts cured at ambient conditions. However, the loss moduli were lower for composites postcured in an oven than their ambient cured counterparts. It was also found that the crosslinking density of the composites slightly increased with particulate (CaCO3) loading and composites postcured in an oven have higher crosslinking density than their counterparts cured at ambient conditions. These results confirmed an increase in stiffness for composites with postcuring treatment. Micrographs by SEM were obtained and confirmed a close inter phase adhesion of the CC filler with the VE resin matrix in the composites. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 2996-3001, 2013