Chemokines, cytokines, and growth factors are signaling molecules that play a crucial role in the coordination of immune responses throughout the body and communication between the immune system and the CNS. Consequently, dysregulation of chemokines, cytokines, and growth factors may facilitate the development of several central nervous system (CNS) diseases. For example, HIV-1 associated dementia (HAD), Alzheimer's disease (AD), and multiple sclerosis (MS) share certain characteristics in their pathogenesis, which include activated macrophage/microglia, production of high levels of proinflammatory cytokines, and impairment of neuronal function. The relationship between disturbances of the immune response and the impairment of neuronal function is the subject of intense investigation. This chapter provides an overview of chemokines, cytokines, and growth factors and their roles in various pathological conditions. Understanding the involvement of chemokines, cytokines, and growth factors in the pathogenesis of CNS diseases may potentially provide the opportunity to identify particular therapeutic targets for the treatment of neurodegenerative disorders. © 2008 Springer Science+Business Media, LLC.