The ability to simultaneously cut and perform hemostasis with low lateral thermal injury makes carbon dioxide laser a useful tool in blepharoplasty. Monopolar electrosurgery is another commonly used cutting tool that improves the quality of hemostasis and cutting speed. This study aimed to objectively and quantitatively assess the intraoperative and postoperative outcomes of transconjunctival lower blepharoplasty using either a carbon dioxide laser or monopolar electrosurgery. Between August of 2018 and March of 2021, 78 patients who underwent transconjunctival lower blepharoplasty were assigned randomly to the carbon dioxide laser group or the monopolar electrosurgery group. Patient-related parameters were recorded. Periorbital bruises were assessed objectively and quantitatively using the ecchymosis evaluation score. Analyses were performed using the independent sample t test, the Mann-Whitney U test, the chi-square test, and the Fisher exact test. Sex, age, local anesthesia injection volume, and fat removal volume were not different between the groups. Patients' subjective intraoperative heat sensation was significantly higher in the monopolar electrosurgery group than in the carbon dioxide laser group. The carbon dioxide laser group had a significantly lower incidence of postoperative chemosis than the monopolar electrosurgery group. All patients had uncomplicated wound healing, except three (7.89%) patients in the monopolar electrosurgery group who developed conjunctival granuloma. Operation time, intraoperative pain sensation, intraoperative blood pressure, postoperative ecchymosis, conjunctivitis, and patients' aesthetic satisfaction did not differ between the groups. The authors' findings revealed that carbon dioxide laser is a useful technique for reducing intraoperative heat sensation and postoperative chemosis and may prevent conjunctival wound complications. Therapeutic, II.