The biochemistry of the venom of Tityus kaderkai Kovařik, 2005 from Madre de Dios department, has been studied. The soluble venom contains 47.6% of protein. The venom proteins were separated from 12.9 mg of venom using cationic exchange chromatography in CM Sephadex C-25 with a 0.05 M ammonium acetate buffer pH 7.0. The chromatography profiles show seven peaks of proteins (I – VII) and five protein bands were distinguished in the crude venom, by PAGE-SDS. The toxicity assays allowed the identification of three toxins affecting Mus musculuswhich were associated to peaks IV, V and VII. Toxic proteins to Gryllus sp. were also found associated to peaks IV, V, VI and VII. Through the enzymatic activity, the presence of proteol...