This study deals with the dynamic mechanical properties of a glass-reinforced vinyl ester resin. The viscoelastic :parameters of the loss factor and the storage modulus as a function of the cure temperature were used as a criterion to determine the optimum cure conditions to be employed. It is shown that the cure temperature usually used to cure these resins is not enough to reach the maximum glass transition temperature, and, therefore, an additional postcure should be used. The influence of several solvents on the dynamic mechanical behavior of these resins cured following the cure pathway proposed by the supplier was also analyzed. This behavior was compared with the solvent uptake at various exposure times, and the changes observed were related to the crosslink density as well as to the chemical structure of both the resin and the solvent. Finally, the effects of varying the exposure temperature were also investigated for the resin exposed to a liquid which simulates petroleum fluid.