Alterations of absolute number or percentage of circulating white blood cell (WBC) subsets are associated with psychological and physical stress. Gender effects on the changes of circulating WBC subsets following surgical treatment have not been determined. Therefore, the current study aimed to determine whether circulating neutrophils, lymphocytes and monocytes, and neutrophil-lymphocyte ratio (N/L) are different following major surgery according to the gender. We studied 409 male patients and 212 female patients who underwent total or subtotal gastrectomy due to stomach cancer, from 1 January to 31 December in 2005. The WBC count and percentage of its subsets were obtained from database and N/L was directly calculated from the full blood count preoperatively, immediate postoperatively, and postoperative day 1, 3, 5 in a retrospective manner. Compared to preoperative values, neutrophilia, lymphopenia, monocytopenia, and increased N/L were associated with gastrectomy in all patients. In the comparison study between genders, there were significantly increased proportion of neutrophils, decreased lymphocytes and monocytes, and higher N/L in female patients than in male patients after gastrectomy. These findings indicate that female patients showed more immune-compromised response to gastrectomy than male patients.