The purpose of this article is aimed at studying the problem of increasing the formation of students’ diagnostic skills in the course of training at a university. The presented article demonstrates a technique for diagnosing the level of professional and cultural competences formation on the basis of students’ effectiveness in quasi professional environment. The basis of the presented work is formed by the ideas of the competence approach, their qualitative tools, expert assessment of the educational activities of university students. The article describes a method of assessing competences, criteria? and levels of formation and methods of their estimation, allowing a diagnostics of educational activities. This article is intended for teachers, researchers, educational institutions heads who deal with the diagnostics of educational activities.