Purpose: The present study attempts to uncover the incidence of and risk factors for inadvertent perioperative hypothermia (IPH) in urological surgery patients. Design: This study was conducted as a cross-sectional study. Methods: The study carried out with 114 patients undergoing urological surgery lasting longer than 30 minutes at a state university hospital. The research data were collected using introductory characteristics form and the body temperature monitoring form. Body temperatures of the patients were measured patients’ preoperative period, intraoperative (early-late) period, and postoperative period. Findings: The results showed that the incidences of early-intraoperative and late-intraoperative IPH were 8.8% and 18.5%, respectively, and this incidence was found to be 40.5% in the postoperative period. Patients’ body temperature was significantly higher in the preoperative period than in the intraoperative-early period (P = .037), intraoperative-late period (P = .01), and postoperative period (P = .000). However, the postoperative period body temperature was significantly lower than that in the preoperative period (P = .000), intraoperative- early period (P = .000), and intraoperative-late period (P = .000) periods. Gender, body mass index, smoking, chronic disease, hemoglobin level, operating room temperature, American Society of Anesthesiologists score, type of anesthesia, exposure to wet drapes, surgical irrigation, and bleeding did not affect patients’ body temperature fluctuations (P > .05). Nevertheless, the volume of intravenous (IV) fluids administered during surgery (≥500 mL) had a significant impact on body temperature changes (P = .002). Conclusions: Overall, IPH developed in the perioperative period in approximately half of urologic surgery patients. Moreover, the administration of greater than or equal to 500 mL of IV fluids to patients was identified as a significant risk factor for IPH. Our findings also highlighted the inadequacy of current protocols for preventing IPH in the operating room. Thus, nurses should employ a combination of passive and active warming techniques to maintain the body temperature of urological surgery patients. Our recommendation is that IV fluids are administered at a temperature above body temperature, particularly in cases where the patient requires greater than or equal to 500 mL of such fluids. © 2025 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.