The relationship between the severity of abdominal discomfort/pain and generic and disease-specific quality of life (QoL) was explored in patients with irritable bowel syndrome in an MCO. Subjects were stratified into four symptom-severity groups. Descriptive and multivariate analyses were used to examine the relationship of QoL to severity of abdominal discomfort/pain. Generic and disease-specific QoL scores declined as severity of abdominal discomfort/pain increased. The lowest 36-Item Short-Form Health Survey scores for respondents with the most severe abdominal discomfort/pain were for role physical (24.2 +/- 35.4) and vitality (33.7 +/- 19.2). In multivariate regression models controlling for age, sex, work status and education, severity of abdominal discomfort/pain was a significant independent predictor of QoL.