The study consists of two parts. In the first, 4,970 subjects were given the occult blood bead (OBB) test and 817 underwent gastroscopy: 40 of those screened were found to have cancer, 30 of which had early lesions (15 had carcinoma in situ). In the second part, a double blind randomized control study of the mass screening was conducted. All the tests were free of charge. Subjects over 30 years of age were persuaded to participate. Two-hundred and eight people accepted the OBB test, gastroscopy and histopathological assessment. A total of four cancers (two early, one moderate and one advanced) were detected by OBB test. If the OBB is carried out properly, gastro-oesophageal cancer is unlikely to be missed. We believe that OBB gastroscopy screening for oesophageal and gastric cancer is reliable and practical.