The World Health Organization has recognized the shortage of competent public health workforce as a major problem worldwide and claimed an urgent need for action. Training public health personnel, effective in an educational perspective, yet with public health relevance in mind, remains a challenge for university-based programs. We present evaluation data of the 25-year experience of a project-centered, problem-oriented, on-job Master in Public Health program at the University of Geneva. Several data collection strategies were used. First, achievement of learning objectives was investigated through content analysis of students’ reports on personal project, through problem-solving final examinations and through self-reported progress on a professional profile. Second, possible public health impact was estimated through analysis of implemented project. Third, yearly discussions with the successive cohorts use the SWOT grid (strengths, weaknesses, opportunities and threats) to investigate the students’ perception of the program. Learning objectives were mainly acquired through community health projects realization, partly also through group work, exercises, readings and lectures. Self-reported progress on a professional profile showed significant acquisitions in all tested public health competencies. All students were able to implement at least one of their planned projects. Students’ perception considered the project/problem-centered approach as positive, but underlined the importance of time constraints and heavy workload in an on-job training program. In our experience a project-centered, problem-based Master program in Public Health allowed students to achieve new competencies and communities to benefit from project implementation addressing public health issues.