The central nervous system (CNS) host a variety of immune cells including macrophages, which are found either in the parenchyma or at the CNS interfaces, such as meninges and perivascular spaces, where they carry out various functions during not only neural development and homeostasis, but in neurodegenerative and neuroinflammatory diseases. Recent emergence of single-cell technologies enhanced our understanding of their origins, fates, and functional heterogeneity of these macrophages during health and perturbation. In this symposium, I would like to discuss the current knowledge about spatio-temporal and functional heterogeneity of CNS macrophages during development, homeostasis and disease, and their potential as a novel therapeutic target for CNS diseases.