Conventional monitoring and evaluation (M&E) textbooks rarely address the various political influences exerted on M&E of public health programs. Policymakers are often the largest consumers of M&E information; indeed, the genesis of many public health program evaluation efforts is a need to inform public policy. People define "political influences", however, as external pressures that may suppress, limit, delay, manipulate, or selectively use M&E outputs. Such forces alter the accuracy and comprehensiveness of assessments of public health problems while coloring the understanding of program progress or effectiveness. Political influences originate from diverse sources and manifest as singular voices or power coalitions including government, industry, religious groups, lobbyists, organized labor, scientists, and special-interest groups. Another often-overlooked source of political influence comes from within the institutions being assessed or those that implement M&E activities. The world of politics is one of value conflict, as Laswell's (1958) definition of politics makes clear; competing policies further different, but not mutually exclusive, goals. It is indeed rare to find situations where compromises are not required or possible. The interaction, then, between politics and monitoring is no different in this respect. These interactions are not static and vary over time based on culture, administrative turnover, and the relative power of special-interest groups. In this article, the authors do not present the overarching politics of human immunodeficiency virus-acquired immunodeficiency syndrome (HIV/AIDS). Rather, the authors concentrate on the effects of discrete political influences on M&E efforts dealing with the HIV/AIDS epidemic and the effectiveness of the response. This article focuses on the HIV/AIDS pandemic to illustrate how political influences have resulted in noteworthy misuses of data, which limit response and fuel both stigma and discrimination. Examples given in this essay indicate where strong, courageous political decisions have significantly advanced the M&E agenda. The authors end with conclusions and possible recommendations on how some of these potential problems can be addressed.