Administration of cimetidine prior to pertechnetate imaging in two patients with Meckel's diverticulum resulted in demonstrating the abnormality with unusual clarity. This is presumed due to the cimetidine-mediated retention of pertechnetate in the gastric mucosa. Pertechnetate imaging in two normal subjects with and without cimetidine administration disclosed a marked difference in retention of the radionuclide in the gastric mucosa and its subsequent transit into the intestinal tract. Pertechnetate imaging in conjunction with cimetidine administration appears to result in markedly improved identification of Meckel's diverticulum.