The purpose of this study was to investigate the potential benefits of additional x-rays in detecting gastric cancer during x-ray screening. We analyzed 151 gastric cancer cases among 136,450 individuals who underwent x-ray screening for gastric cancer. X-rays were performed by 10 radiographers at a single screening center in Japan from 2000 to 2002. Additional x-rays were taken based on the radiographer's judgement in cases of suspected cancer lesions. During reinterpretation of the x-rays of cancer cases by 2 radiologists, we determined the number of cancer cases that were detected by standard x-rays alone. We next determined the number of cancer cases detected using both standard x-rays and additional x-rays. We then investigated whether additional x-rays increased the rate of cancer detection. The number of cancer cases detected by standard x-rays alone was 122 and the number of cancer cases detected by standard x-rays and additional x-rays was 151. We observed a significant increase in cancer detection with the use of additional x-rays when judged necessary by the radiographer (29 cases, P = 0.007, Wilcoxon signed..ranks test). No statistically significant correlation was observed between the number of additional x-rays performed and the increased rate of cancer detection due to additional xrays taken arbitrarily (rs = - 0.38, P = 0.28, Spearman's rank correlation). We found that additional x-rays, performed when judged to be necessary by the radiographer during screening, can identify cases of cancer which are not detectable with the standard x-rays alone.