Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system. However, the clinical features of childhood-onset multiple sclerosis in Asia have been rarely reported. This report presents our experience in 21 patients with multiple sclerosis (15 females, 6 males, mean age 12.4 +/- 4.5 years) in Taiwan with the onset age before 18. The most common presenting symptoms were limb weakness (62%) and visual disturbance (43%). Poly-symptomatic presentations were found in 16 (76%) patients. Magnetic resonance imaging demonstrated basal ganglion involvement in 33.3% of the patients. Neuroimaging and neurophysiologic evaluations revealed optic nerve involvement in 13 (62%) patients. Only one child had the optico-spinal form. Eighteen (86%) patients had a relapsing remission course, whereas three (14%) patients had secondary progressive course. Three (14%) patients initially diagnosed with acute disseminated encephalomyelitis developed multiple sclerosis after 4 months, 2 years, and 6 years, respectively. In conclusion, childhood multiple sclerosis in Taiwan is frequently poly-symptomatic, and is characterized by a higher ratio of optic nerve and basal ganglion involvement. However, the optico-spinal form of multiple sclerosis occurs rarely in children in Taiwan. Our experience suggests that the chance of relapsing should not be overlooked in patients presenting with clinical and neuroimaging findings suggestive of acute disseminated encephalomyelitis.