b＞Purpose/b＞: There has been difficulties in classifying a pathologic subtype of FCD through the various non-invasive diagnostic modalities, although the advent of diagnostic modalities has facilitated the identification of FCD. We studied how the various diagnostic modalities(EEG, MRI, PET, SPECT) can facilitate to clarify a pathologic subtype of FCD. We also studied the prognostic roles of clinical factors and various diagnostic modalities in FCD. b＞Method/b＞: All pediatric patients ,who were proven surgically FCD between Apr. 2003 and Jun. 2008, were analyzed retrospectively. We compared their EEG, MRI, PET and SPECT findings of FCD according to the pathologic classification by Palmini. We also studied the prognostic roles of clinical factors and various diagnostic modalities. b＞Results/b＞: 57 patients were enrolled.(17 microdysgenesis, 4 CDIa, 6 CDIb, 16 CDIIa, 14 CDIIb) In this study, CDIa and CD Ib were put together CDI. Among each diagnostic modalities, only PET had the statistical difference (p0.047) according the pathologic subtypes of FCD by Palmini. In combinations of diagnostic modalities, only the combined EEG and PET had the statistical meaning(p0.011). By univariate analysis, epilesy duration(p0.035) and mild pathologic subtypes(p0.045) were associated with poor surgical outcomes. By multivariate analysis, there was no specific factor associated with the surgical outcomes. The various diagnostic modalities(EEG, MRI , PET) were not associated with the surgical outcomes. b＞Conclusion/b＞: There is a strong tendency for patients with severe pathologic types to have PET abnormalities, and for patients with longer epilepsy duration or mild pathologic types to have a poor surgical outcome. In this study, we may find that even microdysgenesis of FCD had abnormal MRI findings, which is different from previous reports.