Pediatric-onset multiple sclerosis is now recognized, but the association with ethnicity has not been well studied. In a retrospective review at a major teaching facility, 46 pediatric-onset multiple sclerosis patients were identified; of these, 24 were African-American black and 19 were European-origin white. Both groups were similar in mean age at onset (black, 13.6 +/- 3.36 years; white, 13.68 +/- 3.42 years) and total duration of follow-up (black, 42.7 +/- 43.5 months; white, 38.2 +/- 35.3 months), with no significant difference in time to onset of disease-modifying therapy (black, 11.2 +/- 4.7 months; white, 12.4 +/- 5.1 months). The percentage of females was higher in the black than in the white group (83% vs 47%; P = 0.014). The annualized relapse rate was significantly higher in the black than in the white group (1.80 +/- 1.14 vs 1.13 +/- 0.50; P < 0.001). These findings are consistent with data suggesting a more aggressive disease phenotype among African-American blacks with adult-onset multiple sclerosis. Larger multicenter studies are warranted to confirm the findings.