This study aimed to assess factors associated to body temperature changes intraoperatively in patients undergoing elective surgery. A prospective study including 70 patients was carried out in a charity hospital. A data collection instrument was developed and its face and content validity was established. The variables measured were operating room temperature and humidity and patient body temperature at different times. In the multivariate linear regression, the variables type of anesthesia, duration of anesthesia, body mass index, and operating room temperature were directly associated to mean body temperature. Nurses are responsible for planning and implementing effective interventions that can contribute to minimize costs and most importantly reduce hypothermia complications.