Background: This article presents selected outcomes of a 3-year project “Health promotion of school staff in health-promoting schools,” as well as the achievements and difficulties in its implementation. Material and Methods: The research was conducted on 644 teachers and 226 members of non-teaching staff in 21 schools. The method involved opinion poll and authored questionnaires. A 2-part model of outcome evaluation was developed. Results: Most participants appreciated the changes that took place within the 3 years of the project implementation. These included the improved level of their knowledge about health, health-conducive behaviors (62–93%) and the physical and social environment of the school (50–92%). Changes were more frequently acknowledged by teachers. About 80% of the participants had a positive attitude to the project, but only 20% assessed their involvement as considerable. About 90% believed that health promotion activities should be continued. According to the project leaders, insufficient support and financial resources, and difficulties in motivating school employees, particularly the nonteaching staff, to undertake health-promotion activities were the major handicaps in the project implementation. Conclusions: The project outcomes can be assessed as satisfying. They revealed that it is posssible to initiate health promotion among school staff. This can be effective on condition that participants are motivated, actively engaged in the project and supported by the head teacher and the local community. Necessarily, school leaders should be prepared to promote health among adults and to gain support from school policy decision makers, school administration, trade unions and universities involved in teacher training. Med Pr 2016;67(2):187–200