Magnetic resonance imaging (MRI) findings of 20 patients with clinically definite multiple sclerosis (MS) are presented. The studies were performed on a 0.5 Tesla magnet using spin-echo technique. Analysis of the MRI findings included detailed linear measurements of the ventricular and the subarachnoid spaces and reading of the intensity of the grey and white matter and intensity of the MS plaques. The plaques were sorted according to their number and size. The younger patients (20-40 years) had overall more plaques than the older ones (over 40 years). The small plaques were the most numerous and the large ones were the least common. Statistically significant association was found between the number of plaques and the cella media width. The intensity ratios between the non-plaque white matter/grey matter showed a significant correlation with the ventricular score. A significant negative correlation was found between the antero-posterior diameter of the spinal cord and the number of MS plaques in the brain. The plaque/white matter ratio had a significantly negative correlation with the cervical cord's width.