BACKGROUND: Axonal loss is thought to occur early in the course of multiple sclerosis (MS). It is supposed to be associated with, and predictive of, neurologic deficits progressing to permanent disability. Optical coherence tomography (OCT) is used to measure axonal loss in the retinal nerve fibre layer (RNFL). MATERIAL AND METHODS: An observational study was conducted on 20 patients of MS . All subjects underwent neurological examination (EDSS scoring) and OCT on two visits minimum 2 months apart. RESULTS: Total of 40 eyes of 20 patients were subdivided into 14 eyes having optic neuritis (MS – ON group) and 26 eyes without optic neuritis. As the duration of disease increased, RNFL was found to be significantly thinned in all parameters except in the temporal quadrant. Average RNFL thickness were found to have negative correlation (r = –0.440) with disease duration. Negative correlation (r=–0.637) was also found between EDSS score change and average RNFL thickness change. The eyes having optic neuritis showed statistically significant RNFL thinning as compared to the eyes without optic neuritis. CONCLUSIONS: The RNFL thickness is not only significantly thinner in those with history of optic neuritis, but it is also affected remarkably even in absence of prior optic neuritis; suggesting subclinical ongoing axonal loss in patients with MS