Biopower was a term originally coined by French philosopher Michel Foucault to refer to the practice of modern states and their regulation of their subjects through "an explosion of numerous and diverse techniques for achieving the subjugations of bodies and the control of populations." Foucault first used it in his courses at the Collège de France, but the term first appeared in The Will To Knowledge, Foucault's first volume of The History of Sexuality . In both Foucault's work and the work of later theorists it has been used to refer to practices of public health, regulation of heredity, and risk regulation (François Ewald), among many other things often linked less directly with literal physical health. It is closely related to a term he uses much less frequently, but which subsequent thinkers have taken up independently, biopolitics.

For Foucault, biopower, is a technology of power, which is a way of managing people as a group. The distinctive quality of this political technology is that it allows for the control of entire populations. It is thus essential to the emergence of the modern nation state, modern capitalism, etc. Biopower is literally having power over other bodies, "an explosion of numerous and diverse techniques for achieving the subjugations of bodies and the control of populations" It relates to the government's concern with fostering the life of the population, and centers on the poles of discipline ("an anatomo-politics of the human body") and regulatory controls ("a biopolitics of the population").

Biopower for Foucault contrasts with traditional modes of power based on the threat of death from a sovereign. In an era where power must be justified rationally, biopower is utilized by an emphasis on the protection of life rather than the threat of death, on the regulation of the body, and the production of other technologies of power, such as the notion of sexuality. Regulation of customs, habits, health, reproductive practices, family, "blood", and "well-being" would be straightforward examples of biopower, as would any conception of the state as a "body" and the use of state power as essential to its "life". Hence the conceived relationship between biopower, eugenics and state racism.

With the concept of "biopower", which first appears in courses concerning the discourse of "race struggle", Foucault develops a holistic account of power, in opposition to the classic understanding of power as basically negative, and akin to censorship. Sexuality, he argues, far from having been reduced to silence during the Victorian Era, was in fact subjected to a "sexuality dispositif" (or "mechanism"), which incites and even forced the subject to speak about their sex. Thus, "sexuality does not exist", it is a discursive creation, which makes us believe that sexuality contains our personal truth (in the same way that the discourse of "race struggle" sees the truth of politics and history in the everlasting subterranean war which takes place beneath the so-called peace).

Furthermore, the exercise of power in the service of maximizing life carries a dark underside. When the state is invested in protecting the life of the population, when the stakes are life itself, anything can be justified. Groups identified as the threat to the existence of the life of the nation or of humanity can be eradicated with impunity. "If genocide is indeed the dream of modern power, this is not because of the recent return to the ancient right to kill; it is because power is situated and exercised at the level of life, the species, the race, and the large-scale phenomena of the population."