The efficacy of high-concentration barium sulfate has been reported from several perspectives, but not in terms of radiation exposure. This study compared the exposure doses used with high-concentration and moderate-concentration barium sulfate. The exposure dose was evaluated with an experimental method, using a gastric phantom, and with a clinical examination. In the former, the exposure dose and X-ray tube load were measured on the phantom applied with both concentrations barium sulfate. In the latter, the fluoroscopic exposure dose, the radiographic exposure dose, and their sum, the total exposure dose, were investigated in 150 subjects (112 males, 38 females) treated with both concentration barium sulfate. The results of the experimental evaluations indicated that the exposure dose and X-ray tube load were greater with high-concentration barium sulfate than with moderate-concentration barium sulfate (P < 0.05). The results of the clinical evaluations indicated that the fluoroscopic exposure dose was greater with moderate-concentration barium sulfate than with high-concentration barium sulfate (P < 0.05), but the radiographic exposure dose was quite the reverse, so the total exposure dose was the same with both concentrations barium sulfate. We conclude that high-concentration barium sulfate does not increase the radiation exposure in mass screening for gastric cancer.