Abstract The study was aimed at finding what factors in evoked potentials and EEG related to stuttering in subjects 6-25 years of age. Thirty-seven subjects who stuttered and 25 nonstuttering subjects, matched for age, sex and education, were evaluated employing visual evoked potentials, auditory evoked potentials, event-related potentials (P(300)), WISC-(IQ), and electroencephalography. A significant reduction of amplitude of P(100) of visual evoked potentials was found in stutterers with a significant prolongation of wave latencies I, III, V and interpeak latencies I-III and I-V in brainstem auditory evoked potentials. No significant abnormalities were recorded in P(200), N(200) and P(300) of event-related potentials in stutterers compared with the control group. The dominant EEG rhythm was slower in stutterers with a significant interhemispheric asymmetry compared with the control group. Fifty-four percent of the stutterers had pathological EEG. Epileptiform activities were recorded in 16.2% of stuttering subjects. Focal left temporal spike activity was recorded in 5.4% of stuttering subjects. The findings of this study point to a possible role of an organic etiopathogenesis of stuttering.