This paper reports a study that was aimed to evaluate executive functions in relapsing-remitting multiple sclerosis patients. The groups tested comprised 22 relapsing-remitting multiple sclerosis patients, and 22 non-brain damaged controls. When one is engaged in two speeded tasks, not simultaneously but with some form of alternation, it is slower to respond to an item of task A if it was preceded by an item of task B, than when it was preceded by an item of task A. Shifts between sets of cognitive operations can be internally or externally generated. Endogenous task shift refers to advance preparation for the new task. In the present study, we tested endogenous shift cost in relapsing-remitting multiple sclerosis patients. The results indicate a greater shift cost for patients than for non-brain damaged controls.