The conformational behaviour of the biologically active angiotensinogen (6-13) fragment has been investigated by computer simulations. A large sample of conformers has been generated using the Monte-Carlo procedure, then analysed using classification and partition methods. Seven families can describe the conformational distribution. About 40% of conformers are fully extended, 28% are folded at the C-terminal His6-Pro7-Phe8-His9 level and the others are folded at different levels. The study highlights the extreme flexibility of the angiotensinogen fragment.