In the course of modernization of the Russian education system, professionals encounter numerous problems. One of them is the lack of a reliable system of education quality assesment in high school. Since the real level and the real quality of the education in this country are unknown, both educators and potential investors are unable to determine the «convertibility» of educational institutions. International practice shows that it can take decades to solve such problems «from scratch». However, a system of quality assessment has already been developed, and functions successfully within the framework of the International Bacchalaureate organization. Along with hundreds of schools in 119 countries, nine Russian educational institutions now participate in this system. The experience of this system is of course of much interest, and its study and application may well help optimize similar processes in Russia.