Abstract The effect of curing agents (salt, nitrate, ascorbic acid and glucose) and processing parameters (pH, water activity and drying and cooking temperatures) on pork muscle cathepsins B, D, H and L as well as leucyl, arginyl and tyrosyl hydrolysing activities is reported. Salt (60 g/l) showed a powerful inhibitory effect, sepecially on cathepsin D and aminopeptidase activities where less than 13% of the original activity was recovered. Cathepsin H was also affected (38% of the original activity) while cathepsins B and B + L recovered 72.5 and 63.0, respectively. Nitrate (0.2–0.25 g/l) and ascorbic acid (0.2–0.4 g/l) did not significantly affect the enzyme activities. On the other hand, 0.5–2 g/l of glucose activated both cathepsins B and D with an increase of 39.5 and 28.5% and also leucyl and arginyl hydrolysing activities which were 75.0 and 24.0%, respectively. No aminopeptidase activity was detected when assayed in 100 mM sodium citrate buffer, pH 5.1. Cathepsin H was also very affected at that pH and only 12.0% activity was recovered. A decrease in water activity, especially below 0.84, also affected the enzyme activities which were found below 50%. Temperatures in the usual range of the drying process (22 and 30°C) gave substantial enzyme activities (around 40–50 and 80%, respectively). In vitro simulations of different stages in the processing of dry-cured hams and sausages revealed that cathepsins B, B + L, H and leucyl hydrolysing activity were very active (38–82%) in the conditions of ham processing and less favoured (< 36%) in the conditions of fermented sausages processing, especially aminopeptidases and cathepsin H activities which were very low (< 10%) due to the acid pH value. Cooking treatment (65 and 69°C for 15 min) inactivated both cathepsin B and arginyl hydrolysing activities while the remaining activity of the cathepsin H and leucyl and tyrosyl hydrolysing activities were very low (< 4%). The activity of cathepsin B + L was less affected by cooking (61.0 and 25.7%, respectively) as well as cathepsin D (30.0 and 14.0%, respectively) so that both cathepsins D and L might play an important role in cooked cured meat products.