This study investigated short latency cardiac and electrodermal responses in obsessional subjects with cognitive rituals. Three key phrases from anxiety provoking and from neutralizing ruminations were selected as discrete stimuli and presented through a loudspeaker. In addition, three relatively novel phrases were employed. Whereas the anxiety provoking phrases elicited cardiac acceleration, decreases in heart rate followed the novel stimuli. These data suggest that defensive and orienting responses had been elicited by anxiety provoking and novel stimuli, respectively. In contrast, only minimal cardiac reactions were evoked by phrases from the neutralizing rituals. For the electrodermal data, no reliable distinction between the three categories of stimuli was observed. The possible utility of this paradigm as a measure of treatment outcome is discussed.