Double-contrast barium examination of the colon can demonstrate the changes associated with inflammatory bowel disease more completely and specifically than the single-contrast barium study. However, endoscopy is slightly more sensitive than double-contrast examination for detection of disease. In general, between 18% and 20% of patients with Crohn's disease or ulcerative colitis may be expected to have normal radiographic findings but endoscopically detectable disease. However, most false-negative double-contrast colon studies are associated with mild or minimal findings at proctosigmoidoscopy. Although double-contrast radiography may be less sensitive than endoscopy in detection of inflammatory bowel disease, it has similar accuracy for classification and differentiation. Most studies indicate an accuracy of 95% to 98% in differentiating Crohn's disease and ulcerative colitis, due to the fact that morphologic changes detected by the double-contrast mucosal study rarely overlap in the two diseases. Double-contrast barium examination and endoscopy are complementary studies, and the use of both may provide valuable information for evaluation of patients with suspected inflammatory bowel disease.