The philosophy of epidemiology is a recent addition to the philosophy of science. Its focus is on metaphysical and epistemic problems concerning the design and analysis of population studies performed to generate novel knowledge for medicine and public health. The chapter offers a brief introduction to the scope and goals of epidemiology and to a specific discourse about the relevance of Karl Popper’s philosophy for epidemiologists. The chapter also provides three examples of current work in the field: causal inference (with a focus on the work of Alex Broadbent), Olaf Dammann’s work on explanation in public health, and Jonathan Fuller’s work on one central aspect of the “ecological fallacy” in epidemiology, i.e., the question of how to interpret probabilities as individual risk.