BACKGROUND & AIMS: Visceral hypersensitivity is a hallmark of irritable bowel syndrome (IBS), but the relationship with clinical symptoms and psychological factors has not been fully established. We aimed to (1) evaluate these variables in a large cohort of IBS patients, recruited from both hospital and general practice, and in healthy controls and (2) assess which of these factors predicts the occurrence of visceral hypersensitivity in IBS. METHODS: Rectal compliance and perception (intensity, perception thresholds; visual analogue scale, 0-100 mm) were assessed by a rectal barostat study (ramp distention) in 101 IBS patients and 40 healthy volunteers. IBS symptom severity was scored by using a 14-day 5-item diary. Anxiety, depression, somatization, vigilance, pain coping, dysfunctional cognitions, psychoneuroticism, and quality of life were assessed with psychometric questionnaires. RESULTS: Rectal compliance was significantly reduced in IBS patients compared with controls (P < .01), as were thresholds for pain (27 +/- 15 vs 35 +/- 8 mm Hg; P < .01) and urge (P < .05). Levels of anxiety, depression, neuroticism, somatization, and dysfunctional cognitions were significantly increased in IBS patients versus controls, whereas pain coping and quality of life were significantly worse. Hypersensitivity to rectal distention occurred in 33% of patients and was associated with increased symptom severity (P = .016), but not with demographic characteristics or psychological disturbances. CONCLUSIONS: Hypersensitivity to balloon distention occurs in 33% of IBS patients and is predicted by symptom severity but not by psychological or demographic characteristics.