A total of 37 patients who had undergone partial gastrectomy for duodenal or gastric ulcers, were investigated. The postoperative periods ranged from 5 to 28 years. All the patients were subjected to comprehensive clinical and neurologic examinations. The content of vitamin B12 and folic acid in the blood serum was studied by radioimmunoassay in 29 gastrectomized patients, hematological parameters (hemoglobin, serum iron, red blood cell morphology, proteinogram) were estimated in 19 patients. The mean content of vitamin B12 in the blood serum of patients was lower than in normal subjects. The mean level of folic acid in the blood of patients was also lower than in the control, however, this difference was insignificant. Nine patients had subnormal content of vitamin B12, eight of them showed manifest neurologic complications, such as myelopathy and polyneuropathy. Only 3 patients had subnormal content of folic acid in the blood serum. Weakly pronounced anemic syndrome was detected only in 2 out of 19 patients. The role of vitamin B12 deficiency in the development of neurologic symptoms has been considered.