Polyamide 6 was filled with glass fibers or/and quartz sand, processed by injection moulding, electrochem. aged in NaCl solution at pH 7 and 20 degrees C for 720 h (current 0.3 A) and studied for hardness, color, gloss, tensile strength and thermal properties. The ageing resulted in decreasing the hardness, gloss, tensile strength and crystallinity of the composites.