Crohn's disease is often initially misdiagnosed as irritable bowel syndrome. The goal of this research was to determine if computerized auscultation (fasting enterotachogram analysis) could have a role in distinguishing between these diagnoses. Patients with irritable bowel syndrome, Crohn's disease, and a control group were enrolled in the study. The fasting sound-to-sound interval, standard deviation of the interval, sounds per minute, and percentage time involved with bowel sounds was determined by computerized enterotachogram analysis. The mean sound-to-sound interval for the Crohn's group (1232 msecs) and the controls (1706 msecs) was significantly higher than the irritable bowel group (511 msecs, P < 0.0001). We conclude that Crohn's is not characterized by a shortened interval. The high negative predictive value of the fasting enterotachogram for irritable bowel syndrome suggests that an interval greater than 740 msecs should trigger a search for an alternative diagnosis to irritable bowel. Crohn's disease should be included in that differential.