Functional transcranial Doppler sonography was used to study hemispheric language dominance (HLD) in 24 right-handed patients with left temporal lobe epilepsy (TLE) and a structural lesion in the left temporal lobe and in 69 healthy controls. Twenty-five percent of the patients and 4% of controls showed atypical (right or bilateral) HLD. Degree of HLD was not correlated with age, Full Scale IQ, Verbal IQ, spike frequency, seizure frequency, age at seizure onset, or duration of TLE. Atypical HLD appears to be lesion-induced, independent of epilepsy characteristics.