The role of the anterior cingulate in the counting Stroop task was examined using transcranial magnetic stimulation (TMS). TMS was given over sites targeting more dorsal and more ventral anterior cingulate cortex and a control area of parietal cortex whilst subjects reported the number of words presented on the screen using a key press. The Stroop interference effect was abolished by TMS over both anterior cingulate sites. These findings support functional neuroimaging research which suggests that cingulate cortex is central to the processes underlying the Stroop task.