This paper begins with an examination of a genealogy of philosophical reflections on health and illness from Friedrich Nietzsche to Georges Canguilhem and Gilles Deleuze. While Nietzsche’s inspiration to Deleuze has been widely acknowledged, little attention has been paid to how Canguilhem’s philosophy of the life sciences follows Nietzsche and later affects Deleuze. Canguilhem claims that health is one’s feeling of confidence in life; health is when a living being feels it creates values and establishes its own vital norms. The notion of individuality plays a significant role in Canguilhem’s philosophy of the life sciences. Individuality is not only constituted by a living being who determines how to react; for Canguilhem, individuality refers to a living being as well as its relation to the milieu. An individual is not pre-given; instead, in selecting and responding to its milieu, it is individuated. Understood in a biological sense, the individual, when creating a norm, makes a judgment based on feeling. While a norm is created, the assessment is where values are posited. For Canguilhem, to live is to evaluate, to seek the sense of the organism’s choice. Hence the notion of individuality is considered as an axiological rather than an ontological one. This paper is composed of three parts: the living and its milieu, individuality and valuation, and Canguilhem and contemporary medical issues. I intend to examine why and how Canguilhem’s notion of individuality is tied to value judgements, what influence Nietzsche has on Canguilhem, and how Canguilhem’s thoughtful ideas of individuality can help us critically reflect on contemporary debates about personalized medicine.