Multiple sclerosis (MS) does occur in India but it is rare. No epidemiological studies have been done. The calculations based on the hospital data suggest an approximate prevalence rate of 0.17 to 1.33 per 100,000 of population in different parts of India. One hundred and five patients with clinically definite MS (2 proven at autopsy) and 14 patients with neuromyelitis optica were seen in the Bombay region from 1957 to 1983. The mean age of onset for MS patients was 27.7 years. There were 60 female and 45 male patients. The clinical data in this larger series confirm the conclusions reached earlier, namely that the Indian MS patients are more akin to those reported from Japan and other Asian countries as compared to the West. The relative incidence of neuromyelitis optica was high (6%). The optico-spinal form of MS was the commonest (71.4%). In patients with clinically definite MS there was a high incidence of optic nerve involvement, both at the onset and during the course of the disease; sensory level occurred in a large number of patients and cerebellar involvement was less frequent. Multiple sclerosis in this series affected patients of all communities and different dietary habits. MS was more common in the higher socioeconomic group whereas neuromyelitis optica was mainly seen in patients in the low socioeconomic group.