The complex neural organization of autonomic nervous system (ANS) extends throughout the central and peripheral nervous systems. As a chronic demyelinating disease of the central nervous system characterised by disseminated lesions, multiple sclerosis (MS) can cause multiplicity of clinical features including those related to the involvement of the ANS. In order to assess some possible autonomic dysfunctions in MS 39 patients with definite MS, according to Poser criteria, were included in addition to 20 healthy volunteers in this study. MRI brain and spinal cord and evoked potential studies were performed for patients to confirm diagnosis. All subjects were subjected to: questionnaire for autonomic symptoms, general and neurological examination, including EDSS for patients, blood pressure measurement while supine and after standing, electrophysiological tests for assessment of cardiovascular autonomic function, which included heart rate variability measurement in 24-hours ECG recording; assessement of RR interval variability during: normal and deep breathing, standing up, and Valsalva maneouvre, sympathetic skin response (SSR) for assessment of sudomotor function, and evaluation of gastric motility by scintigraphy. Autonomic function impairment was found to be common in MS patients, on the clinical level the most common being bladder, in addition to bowel and sexual dysfunction. Postural hypotension was encountered in 41%. On a subclinical level, SSRs were abnormal in over 90%, cardiovascular reflex abnormalities were found with deep breathing (54%), standing up (59%), and Valsalva manoeuvre (36%). Gastric emptying was slower in patients than controls but the statistical significance was not achieved. Only postural changes in SBP were associated with corpus callosum lesions. No relation was found to age or gender of patients, duration of disease, number of attacks, or EDSS score.