While functional gastrointestinal complaints are common in the elderly, valid instruments for their assessment are lacking. We have developed the elderly bowel symptom questionnaire (EBSQ) and report its feasibility, reliability, and validity in medical outpatients and a larger sample of the community (aged 65-93). Reliability was measured by a test-retest procedure, while concurrent validity was documented by comparing physician interview and self-report data. Reliability (median kappa 0.65, interquartile range 0.49-0.79), and validity (median kappa 0.68, interquartile range 0.51-0.80) were very acceptable. A random sample of 424 independently living elderly persons was obtained; 77% replied to the mail survey. Medical record review showed that no current diagnosis of irritable bowel syndrome was missed by the questionnaire. Our results confirm that the EBSQ was easy to understand and well accepted, and was a reliable and valid measure of gastrointestinal symptoms in older persons; this instrument may have important clinical and research applications.