The measured mechanical properties of carbon fiber/polyamide 6 (CF/PA6) laminates decreased with exposure time at 60°C and 100% relative humidity. Both the bending stiffness and the strength degraded to a level of about 65%, whereas interlaminar shear strength (ILSS) dropped to about 87% of the property values of the unexposed material. The bending stiffness and strength at -45°C are about 87% of the properties at room temperature, whereas at 115°C, the stiffness drops to 75% and the strength drops to 60% of the properties at room temperature. The ILSS values also drop to about 75% at both -45°C and 115°C. Extreme temperatures and longtime exposure to humidity of quasi-isotropic CF/PA6 laminates can thus reduce the bending stiffness and strength by up to 35% and the ILSS by up to 25%.