Netherton syndrome is a severe ichtyosis caused by mutations in the SPINK5 gene encoding the protease inhibitor LEKTI. It is mainly characterized by a disrupted epidermal barrier, chronic inflammation and structural abnormalities of hair shaft. Patients with Netherton syndrome and mouse models deficient for LEKTI exhibit increased proteolytic activity in the epidermis. To elucidate the role of the individual proteases KLK5 and KLK7 in LEKTI deficient epidermis, we have prepared a set of mouse models deficient for LEKTI, double deficient for LEKTIxKLK5 and LEKTIxKLK7 and triple-deficient for LEKTIxKLK5xKLK7. We observe an improvement of a number of cutaneous symptoms of Netherton syndrom in both double deficient animal models and full rescue of Netherton syndrome-like phenotype in LEKTIxKLK5xKLK7. These data provide in vivo evidence that KLK5 and KLK7 are the main cause of epidermal pathologies in Netherton syndrome patients and help us to understand the role of these proteases in the disease.