Snake venoms are rich sources of serine proteinase inhibitors that are members of the KunitzBPTI (bovine pancreatic trypsin inhibitor) family. Generally, these inhibitors are formed by 60 amino acids approximately. Their folding is characterised by a canonical loop that binds in a complementary manner to the active site of serine protease. Some variants from snake venoms show only weak inhibitory activity against proteases while others are neurotoxic. Moreover, proteases inhibitors are involved in various physiological prdcesses, such as blood coagulation, fibrinolysis, and inflammation. Also, these molecules showed an anti-tumoralpotent and anti-metastatic effect. Interestingly, KunitzBPTI peptides can have exquisite binding specificities and possess high potency for their targets making them excellent therapeutic candidates.