We contemporarily studied cerebrospinal fluid (CSF) and peripheral blood (PB) T-cell subsets, defined by monoclonal antibodies, in 29 patients with multiple sclerosis (MS) and 10 patients with other neurological diseases (OND). All subjects showed a clear-cut prevalence of CSF T-cells. Similarly, T-helper and T-suppressor subsets tended to show higher percentages in CSF in almost all subjects except relapsing MS, who were characterized by low percentages of T-suppressors in PB and even much lower percentages in CSF. Helper/suppressor ratios were found to be almost similar in the two body compartments of OND patients, lower in CSF than in PB of chronic progressive MS, always higher in CSF than in PB of relapsing MS. MS patients in remission showed both patterns of progressive MS and OND patients. Our results demonstrate that the loss of PB T-suppressor in relapsing MS is not due to a migration of such cells into CSF. Furthermore, regarding T-lymphocyte subsets, a typical CSF/PB pattern characterizes relapsing MS from other patients.