This cross-sectional study was performed to evaluate the relationship between intraoperative body temperature and the need for blood transfusion and length of stay in the post-anaesthetic care unit (PACU) or in the intensive care unit (ICU) among 79 patients undergoing elective oncology surgery of the digestive system. There was a statistically significant correlation between a lower temperature during surgery and medical diagnosis (p = .009), the use of bupivacaine anaesthesia (p = .016), anaesthesia time (p = .003) and anaesthesia type (p = .033), surgery time (p = .021) and surgery type (p = .002), volumes infused during the intraoperative period (p = .006), admission to the ICU (p = .032) and length of stay in PACU (p = .029). The lower the temperature when the patient is admitted to the operating room, the lower the temperature during the procedure (p < .001). There was no association between the body temperature of patients and blood transfusion (p = .619). Hypothermia was associated with increased length of stay in the PACU, but was not associated with the need for blood transfusion during the intra- and postoperative periods. The use of preoperative passive warming methods allows patients to reach the operating room hypothermic.