BACKGROUND/AIMS: Patients suffering from irritable bowel syndrome (IBS) tend to have extraintestinal symptoms. The purpose of this study was to compare the nature and severity of the urinary symptoms in IBS patients in comparison to non-IBS patients. METHODS: From July 2004 to August 2004, an internet survey was carried out by sending e-mails to 50,000 subjects aged from 18 to 49 who had registered with an internet research company, and they were requested to join our study. RESULTS: A total of 504 women (mean age: 28.7+/-6.0) completed the questionnaire via an internet web site. The overall prevalence of IBS by the Rome II criteria was 23% in the young adult women. The factors associated with the prevalence of IBS were smoking and a high body mass index. The urinary symptom scores were not statistically different between the IBS patients and the non IBS patients (10.1+/-8.2 vs 9.2+/-8.9, respectively, p value 0.34). However, the IBS patients felt more distress and a lower quality of life due to their urinary symptoms than did the non-IBS patients. In particular, nocturia was the most distressing symptom. CONCLUSIONS: Although the urinary symptom scores were not statistically different between the IBS patients and non-IBS patients, IBS patients felt more distressing urinary symptoms than did the non IBS patients.