The majority of surgeries performed in hospitals are related to the abdomen. Many patients develop complications after surgery, and nurses are the primary caregivers for the patients after surgery. Studies have shown that the number of elderly patients with life-threatening abdominal diseases undergoing emergency surgeries is increasing. The common problems arising after surgery performed under general anesthesia are altered thermoregulation and circulatory complications. One of the strategies to reduce post-operative complications related to thermoregulation in abdominal surgery is warm, humidified oxygen intervention. The objectives are to assess the pre-intervention data on thermoregulation in the experimental and control groups, determine the effect of warm humidified oxygen on thermoregulation in the experimental group, assess the post-intervention data on thermoregulation in both groups, and associate the thermoregulation with selected background variables in both groups. The purposive sampling technique was adopted to select the participants. The study comprised 40 patients who fulfilled the inclusion criteria. The research tools included a demographic profile, a shivering score, physiological parameters, and other parameters. The data was analyzed quantitatively in terms of frequency and percentage, mean, standard deviation test, ANOVA test, and Fisher exact test. The findings of the study revealed that the warm humidified oxygen intervention is helpful in increasing temperature and reducing shivering in the experimental group, and the alternative hypothesis is accepted. The study results will be very useful in nursing practice because nurses can use this method to increase body temperature, reduce shivering, help with oxygen saturation, and reduce the incidence of dry mouth.