The chapter focuses on the role of the heart and the image of the world as a cardiovascular system in the post-Chrysippean tradition. Within this picture, then, it will be shown that in later Stoicism, not only the heart but the blood first and foremost was used in explaining the essence and features of the soul and eventually employed as a model to explain the universe. The existence of a ‘hematic’ variation within cardiocentrism will thus be highlighted, which allows some Stoics to better justify the spreading and the action of the soul within the body, and that of god throughout the cosmos. By doing so, the post-Chrysippean tradition recalls Empedocles’ position. This topic will be first of all studied in Diogenes of Babylon, who stresses the importance of the heart in the wake of his master Chrysippus, yet apparently providing a different definition of the soul as (made of) blood. The chapter examines then Posidonius, whose cardiocentrism – though not strictly ‘hematic’ – differs from that of both Aristotle and Chrysippus and is crucial for his understanding of living beings and natural phenomena. Lastly, the contribution considers Seneca and Manilius, who often represent the universe as a cardiovascular system enlivened by a network of blood vessels.