Because of the rarity of Multiple Sclerosis (MS) in childhood, the child with suspected MS may present a difficult diagnostic problem. There have been relatively few number of clinical reports of cases with onset of MS under the age of 16. We present clinical data from 23 patients with MS who had onset of disease before 16 years of age, that is 5.6 % of a total population of 412 MS patients. The average age at onset was 13.2 years and the average duration of the disease was 12.1 years. Twenty (78 %) patients had definite MS, 3 patients (13 %) had probable MS according to Poser's criteria. Family history was positive only for one patient. Fifteen (65.2 %) patients had a relapsing-remitting course, 6 patients (26.1 %) had secondary progressive course, 1 patient (4.3 %) had primary progressive course, and 1 patient (4.3 %) had first attack. One patient died during follow-up period. On last control, the average EDSS score was 3.42. Percentage frequencies for neurologic deficits in our patients were brainstem involvement 78.3 %, pyramidal signs 60.9 %, cerebellar signs 52.2 %, optic neuritis 47.8 %, myelopathy 26.1 %, and mental impairment 4.3 %. MRI was performed in 18 patients and 16 of them (88 %) had cerebral white matter lesions in T2 weighted images. In twenty-one patients multimodality evoked potentials were examined, both VEP and SEP showed abnormalities in 14 (66.6 %) of them, BAEP abnormalities were obtained in 8 (38.1 %) of them. In this study, we discussed our findings with the findings of other studies of childhood MS and compared the differences with adult onset cases.