In spite of all the efforts and successes during the last twenty years corruption remains a major ethical challenge around the globe and one of the main obstacles to development. This study concentrates on a sector, on which not many publications are available: churches, mission organizations and development agencies. Both are sometimes part of the problem and can contribute a lot to solutions. Experiences of and with churches and development agencies during the last fifteen years (1995-2010) are herewith described and reflected. The author shows that ethical and theological orientation motivates for action. By collecting successful codes of conduct and guidelines the study focuses not on problems, but on solutions. The study includes 35 concrete recommendations. It further contributes to resist resignation and gives hope: corruption-free churches are possible!