Recent imaging studies provide evidence that stuttering may be characterized by abnormal cortical auditory processing during vocalization. Taking advantage of the high temporal resolution of electroencephalography, this study measured auditory evoked potentials of stuttering and fluent speakers during vocalization. In addition to a normal vocalization condition, evoked potentials were recorded during a binaural white-noise masking condition. Subtraction of the two conditions allows isolation of the auditory self-monitoring cortical response. Results for control subjects showed a clear response at a latency of +I00 ms. Responses among the stutterers were varied including normal response, lack of response, and possibly early response. One stuttering subject showed hemispheric differences in response. These results appear to support the hypothesis that abnormal auditory self-monitoring during vocalization is a characteristic of some persons with persistent developmental stuttering.