Central nervous system (CNS) inflammation occurs in a large number of neurological diseases. The type and magnitude of CNS inflammation, as well as the T-cell contribution, vary depending on the disease. Different animal models of neurological diseases have shown that T cells play an important role in CNS inflammation. Furthermore, recent studies of human neurological disorders have indicated a significant role for T cells in disease pathology. Nevertheless, how individual T-cell subsets affect neuronal survival, damage and/or loss remains largely unclear. In this review we discuss the processes by which T cells mediate either beneficial or deleterious effects within the CNS, with emphasis on the direct interaction between T cells and neurons, as occurs in multiple sclerosis, paraneoplastic cerebellar degeneration, and viral encephalitis. The therapeutic approaches targeting T cells and their mediators as treatment for neurological diseases are also described here. This article is protected by copyright. All rights reserved.