The preliminary results of an on-going SAKK study on metastasising mammary cancinoma are reported. At the time of writing 210 cases are already evaluable. This study seeks to investigate the question of the necessary intensity of polychemotherapy and also the problem of whether cytostatic therapy should be begun at the same time as hormonal therapy or just after failure of this measure. At present no definite answer is available. The results point to a new, possibly important aspect of the treatment of metastasising mammary carcinoma.