BACKGROUND: Perioperative hypothermia is the decrease in temperature, below 36 °C after surgery that is linked to immediate and late complications. The control of hypothermia reduces morbidity, mortality, and the time of integration of patients to their social and family environment. The objective of the present study is to determine the prevalence of inadvertent hypothermia and associated factors in the immediate postoperative period. METHODS: The present is a cross-sectional analytical study, working with male and female patients from 18 to 70 years old, undergoing elective surgeries at the Hospital Vicente Corral Moscoso, from May 16 to August 11, 2016. It was evaluated the temperature with an electronic thermometer and the associated variables through a form prepared by the researchers. The statistical programs PSPP 0.10.4 were used for the bivariate and multivariate analysis and EPI INFO 7. RESULTS: Of the 267 patients investigated, 68.5 % developed hypothermia in the immediate postoperative period. General anesthesia increases 1.8 times the risk of developing hypothermia with a statistically significant value, as well as an anesthesia time greater than 60 minutes but with a value of borderline significance. CONCLUSIONS: The factors associated with the development of hypothermia are: the use of general anesthesia and the anesthetic exposure time greater than 60 minutes. We recommend taking temperature in patients before, during and after the surgical procedure, to act in a timely manner before the onset of hypothermia.