The study analyses strengths and weaknesses of the 'Paying For Performance' (P4P) approach rolled out in the Rwandan health sector since 2002. It uses three research methods: a cross-sectoral literature review on P4P, its history and its context; 69 mostly semi-structured interviews conducted in Rwanda; and an analysis of factors eventually confounding the impact evaluation of the Rwandan P4P approach. It is argued that P4P approaches can be traced backed in written form over four millennia and that considerable negative effects are reported throughout history. All side effects were found again in various forms in the Rwandan health sector. One particular side effect -'gaming'- seriously threatens to affect the quality of health services. It is argued that P4P implicitly (and unintentionally) promotes a questionable concept of human 'labour' and that its focus on improving indicators rather than systemic changes can be regarded as vertical and counter-productive. Two alternatives to the current P4P system are briefly depicted, and further research on the described challenges is recommended.