We investigated the validity of the 2005 and 2010 McDonald magnetic resonance imaging (MRI) criteria for dissemination in space (DIS) to predict the conversion of clinically definite multiple sclerosis (CDMS) in 94 Korean patients with clinically isolated syndromes (CIS). The sensitivity, specificity, accuracy, positive and negative predictive values of the 2005, 2010 McDonald DIS criteria were comparable to those observed in the Caucasian population. This finding suggests that after careful exclusion of alternative explanations, particularly neuromyelitis optica (NMO) and NMO spectrum disorder (NMOSD), both the 2005 and 2010 McDonald DIS criteria are also useful to predict conversion to CDMS in Korean patients with CIS.