This study aims at investigating primary school principals' work on a daily basis in order to understand the ways in which the centralized educational system affects their practices. Four typical cases of principals were selected and asked to keep daily records for a period of four months. Data from logs were complemented with data collected through semi-structured interviews with the principals as well as through discussions with the teaching staff. Results show that the transactional-bureaucratic model in line with the current legislation and administration tradition shapes principals' activities to a large extent. School administration, school organization and internal relationships are the most important areas of principals' activities. Educational-pedagogic issues constitute only a marginal area of their activities. The homogenization of principals' activities is so high that they do not seem to be affected either by school contextual factors or by the individual principals' personal traits. However, features pointing towards a more transformative-instructional model of leadership were identified. These features are: (a) the democratic-participative nature of decision-making, (b) the intimate relationships existing in most schools and (c) the motivation that some principals have towards creating a unique identity of their school and communicate it to the hierarchy and the community.