Serum ferritin values were measured preoperatively in 83 patients with gastric cancer and were found to be significantly higher than in normal subjects and mammary cancer patients. They were also significantly higher in healthy men than in women and in gastric cancer patients at stages I and IV than in those at stage III. There was no significant correlation between the serum ferritin value and various immunologic parameters. OK-432 serially administered pre- and postoperatively (A) and only postoperatively (B). The ferritin value increased markedly at one week postoperatively, reaching a peak at two weeks; at four weeks, it was reduced toward the value at one week. However, these changes in ferritin value showed no significant difference between groups A and B.