Introduction & Objective: Multiple Sclerosis (M.S) is common demyelinating diseases that is presented by inflammation and destruction of myelin of central nervous system such as different sizes of plaques. There are several methods for diagnosis of pathological findings in M.S., and one of them is MRI that is magnetic Resonance Imaging. In this study clinical manifestations and pathological findings of patient's MRI in M.S. and also the relation between severity of signs and progression of MRI plaques were evaluated.

Materials & Methods : This was a descriptive cross sectional sudy that carried out on 60 patients with multiple sclerosis , in department of neurology of Hamadan Sina Hospital in 4 years (1999-2003). Clinical manifestation , age, sex, family History and past history of infectious and psychological diseases were evaluated. M.S characteristics like size, numbers and distribution were studied and collected data was analyzed with EPI6 software.

Results: There was a positive relationship between severity of clinical manifestations and low ages and history of several viral infections but there was not statistical relation between severity of manifestations and plaques criteria's as their diameter, size and dispersion of plaques in MRI.

Conclusion: It was concluded that it is not possible to predict the severity of symptoms of MS according to the MRI results , solely , but study of both factors simultaneously is necessary in proper evaluation and diagnosis of the disease.