The article deals with the problems of psychological diagnostics of a person’s intellectual abilities. The author argues that, when interpreting the results of intelligence testing of a particular individual (whether child or adult), it is neither possible to diagnose correctly the person’s real intellectual resources nor predict the direction in which this potential will develop. The article discusses professional and ethical principles of applying intelligence tests as well as the social and ideological aspects of testing. Arguing from a stated developmental paradigm, the author attempts to draw limits within which psychometric intelligence tests can be used, and she also addresses the issue of protecting the rights of a personality.