A comparative analysis of results of the pre- and postoperative investigations carried out in 232 patients with gastric ulcerations of different nature has shown a relatively low effectiveness of fibrogastroscopy with biopsy in the recognition of malignant ulcers. The sensitivity of this method was found to be (83 +/- 3)%. The results obtained show the necessity to widen the operative treatment of patients with ulcer disease of the stomach, patients with the so called relative indications included.