Fifty-eight children were studied for the presence of Meckel's diverticulum by scintigraphy with 99mTc-pertechnetate. Meckel's diverticulum was found at surgery in 6 of 6 patients with positive radionuclide studies and in 2 of 48 patients with negative studies. Four studies could not be interpreted because of widespread intestinal activity. Using the criteria described in this paper, false-positive readings did not occur.