Turner's syndrome (TS), resulting from deletion of one X chromosome in women, is associated with cerebral development abnormalities, particularly in the temporal lobes. Symptomatic epilepsy is described only in cases with extensive malformations. Here, we report the first case of bilateral temporal epilepsy without macroscopic cerebral malformation in a woman with TS mosaicism. Bitemporal dysfunction was confirmed by the ictal and interictal EEG, PET, MR-spectroscopy and the neuropsychological examination, other causes than TS mosaicism were excluded. In rare cases, TS mosaicism may underlie non-lesional temporal lobe epilepsy, probably in relation to microanatomic structural and functional cerebral abnormalities. Further studies are needed to determine the frequency of this association.