A comparison of the results of non-aimed large-frame fluorography (LFF) and roentgen study of the stomach in 301 patients enabled ascertaining more precisely the opportunities of LFF in diagnosing gastric cancer. It was found by checking (fibrogastroscopy with biopsy or surger) that irrespective of the technic of non-aimed LFF, despite the diagnosis being known previously, cancer of the stomach still far from being in early stage may be recognized only in 62-63%. Therefore use of non-aimed LFF to diagnose gastric cancer during mass prophylactic examinations seems to be not rational.