The disability outcome related to the presenting signs and symptoms was studied retrospectively in 193 patients with definite multiple sclerosis (MS). Patients whose first sign was motor weakness were found to be more severely disabled, at all stages throughout the course of the disease, than patients with other presenting signs or symptoms. Patients whose disease manifested initially with sensory disturbances or paraesthesiae proved to be less seriously disabled than other patients at all stages of the disease. A similar tendency was found in patients presenting with optic neuritis (ON) for the first 20 years of the disease; after that, their disability was comparable to that of patients with other presenting complaints. The difference during the first 20 years of the disease is mainly due to the asymptomatic period after initial manifestation of optic neuritis.