A prospective study was carried out in 207 patients with benign and neoplastic diseases of the digestive tract who were candidates for elective surgery, in order to evaluate the influence of the nutritional status and perioperative transfusions on the appearance of postoperative infections. All patients were subjected to a nutritional assessment study based on anthropometric parameters, analytical data, and cutaneous delayed hypersensitivity tests. With the aim of establishing a risk potential for postoperative infection based on the nutritional status of the patients, a multi-parametric index called Nutritional Septicemic Risk (NSR) was applied to all. NSR = 14.265 - 1.764 + Albumin - 1.472 x risk area The criteria that were considered to indicate Proteic Caloric Malnutrition (PCM) were the presence of a Usual Weight Percentage (UW%) lower than 90% and an albumin level lower than 3.5 g/dl. Transfusions were indicated at Hemoglobin levels lower than 10 g/dl and/or a Hematocrit lower than 30%. The perioperative transfusion was defined as that which took place within three weeks prior to the surgery, during the surgery itself, and that which took place during the first 48 hours postoperatively. The postoperative infections have qualitatively been evaluated as: infection of the surgical wound, intraabdominal abscess, and respiratory infection. A total of 80 patients (38.6%) showed some degree of malnutrition. With regard to the transfusions, 55 patients (26.6%) underwent a transfusion. The univariable study has identified the nutritional status as classified according to the NSR multi-parametric index, neoplastic disease, perioperative transfusion and a surgical intervention time greater than two hours, as being risk factors of infection. By means of the logistic regression study, the nutritional status (NSR score) and the perioperative transfusions have been identified as independent risk factors.