The aims of this study were to determine whether increased pain sensitivity in patients with irritable bowel is due to physiological differences in perceptual sensitivity or psychological influences on perception, and whether prior sexual abuse accounts for increased pain sensitivity. Seventeen sexually abused and 15 nonabused women with irritable bowel were compared to 13 sexually abused and 14 nonabused women without irritable bowel. Among the nonabused subjects, the volume of rectal distension that produced moderate pain was lower in IBS patients than in controls, replicating earlier studies, but these thresholds were correlated with psychological measures of anxiety and somatization. The ability to discriminate between painful distensions (perceptual sensitivity) was not different between groups. Sexual abuse was not associated with lower pain thresholds. Thus, differences in pain sensitivity appear to be due to psychological influences on perception, but a history of sexual abuse does not contribute significantly to this pain sensitivity.