This study aimed to investigate the relationship between cathepsin B activity and muscle firmness of dry cured hams. A total of 988 samples of semimembranosus muscle were collected from raw hams of heavy pigs and cathepsin B activity was determined using fluorimetric method. Raw hams were cured following San Daniele guidelines. Dry-cured hams were deboned and cross-sectioned. On the cross section firmness was measured at three muscular sites (M. semimembranosus, semitendinosus and biceps femoris) using a Hardness Meter MK2. This study did not evidence any significant relationship between cathepsin activity and firmness of dry cured hams.