The main objective of this paper is to show to what extent and why students with the same academic aptitude but different social backgrounds have different odds of entering university. For our analysis, we separated primary and secondary factors of social origin in the formation of educational inequalities. The results show that the primary and secondary factors have approximately the same influence on the transition to university. Czech schools do not affect the process of forming educational aspirations and transition to university, and merely "classify" children according to their social origin. This situation emerged during the socialist era and has remained unchanged after the fall of communism (in 1989). However, the mechanism of the social origin effect has changed--while cultural capital with a "direct" impact had a major role to play during the socialist era, at present there is a rather "indirect" influence through economic capital.