The "state of art" in the problem of BSE and its role in breast cancer early diagnoses in analysed. Advantages and disadvantages of this method and a complex of socio-psychologic problems arising in healthy population due to its introduction are discussed. The absence of scientifically grounded data on the importance of BSE for early diagnosis of breast cancer suggests the necessity of further investigations in order to identify its efficacy. Such data can be obtained only on the basis of randomized population study with estimation of efficacy by the decrease of breast cancer mortality in population. Under the auspices of the WHO such investigation has been conducted in Leningrad and in Moscow (USSR). Methods or investigation applied are described in short.