Two accelerated hot-wet aging tests of glass-reinforced epoxy resin were performed at 45 and 70°C at the same level of relative humidity (RH = 84%). Mechanical and physical properties of “dry” and differently saturated composites are compared. It has been found that the higher the conditioning temperature, the higher the equilibrium moisture content. The glass transition temperature decreases from 138°C (dry) to 108 to 111°C (for both moisture saturated cases). Moreover, it has been found that moisture absorption reduces the static properties while not modifying the endurance in fatigue tests.