Abstract Janet suggested a disorder of attention was fundamental to hysteria. This idea was investigated in this study by examining mismatch negativity (MMN), which depends upon a subtraction of cortical potentials evoked by background stimuli from those evoked by target stimuli. Ten patients with somatization disorder (SMD) were compared with ten normal individuals. MMN was smaller in somatizers, particularly at the central recording site. One interpretation of this observation is that somatizers respond more similarly than normals to “relevant” and “irrelevant” stimuli. This finding of an impairment in attentional processing in somatization disorder suggests a subtle neurophysiological disturbance.