Repetitive dysfluencies of speech were elicited by mechanical perturbation of the thalamus in a patient, preparatory to therapeutic lesion placement for chronic pain. Perturbation consisted of a 2 mm advancement of a 1 mm diameter electrode in the posteroventromedial thalamus. A thalamogram revealed electropathologic discharges at the site of perturbation. These findings are of special interest anatomically because in other patients, electrical stimulation at the same site was found to alleviate stuttering (Andy, 1987; Andy, 1989; Andy & Jurko, 1985; Bhatnagar & Andy, 1989). It is suggested that dysfluencies in this patient may have resulted from an electrophysiologic disturbance of the mesothalamic component of a speech-regulating corticomesothalamic feedback circuit.