My project concerns the relevance of the concept of ‘natural kind’ to our understanding of scientific practice, particularly within the life sciences. As such it seeks to affect a change in our philosophical thinking away from treating natural kinds as an issue or problem of ontology towards understanding them in terms of their fundamental epistemic roles in scientific practice. Most modern discussion of ‘natural kinds’ these days does in fact occur with respect to the life sciences, where the concept seems central to claims of these fields but at the same time deeply problematic. It has been tremendously philosophically difficult saying what natural kinds are in this context when many examples of them such as ‘species’ seem not reducible to a precise set of essential properties, but admit exceptions, historical changes in their descriptions or multi-realisability. This failure has prompted the question whether there is in fact any value in a ‘natural kind’ concept at all (see Hacking), given it seems impossible to say what we are really referring to by them. I believe however this is premature as it fails to appreciate the deep conceptual and investigative roles that concepts considered ‘natural kinds’ play in the life sciences as often the very basis around which these fields are organised. It is thus in the context of elaborating and accounting for practice that the concept of natural kind is required. My project sets out to argue that philosophers should take an epistemic-only view of natural kinds whereby our task is to understand their epistemic contributions to scientific practice (as bases of categorisation, inductive generalisation and explanation), and the way in which research processes conceptually depend upon them. With this perspective the sense of ‘natural’ of the concept is not interpreted ontologically, but rather is cached out in terms of the beliefs scientists have towards the concept and how this affects their use of it. This project will develop this viewpoint with respect to case-studies from the life sciences, where the aim is to investigate how the ‘natural kind’ concept is epistemically central to research practices. I will argue that with this approach to natural kinds we stand to have a better understanding of the basis upon which research processes, and in turn conceptual frameworks, evolve.