Objective: To compare the outcome of monopolar cautery and conventional surgery in the treatment of ankyloglossia. Intra-operative bleeding is the primary outcome, with operative time, post-operative maternal pain score, LATCH score, and complication being the secondary outcome.Patients and Methods: The randomized, controlled trial recruited newborns diagnosed with ankyloglossia using the Hazelbaker Assessment Tool in the department of Otolaryngology, HRH Princess Maha Chakri Sirindhorn Medical Center (MSMC). The patients were randomized into either the conventional group or cautery group (monopolar cauterization). Pre-operative, intra-operative, and postoperative data were recorded.Results: 32 infants diagnosed with ankyloglossia were randomized into two groups; conventional group (n=16) and cautery group (n=16). The result shows a statistically significant lower incidence of intra-operative bleeding in the cautery group (n=1) when compared to the conventional group (n=10) (p-value=0.003). The cautery group also has a significantly shorter mean operative time than the conventional group; three (2 to 6 minutes) compared to five                                                             (3 to 13) minutes respectively (p-value=0.001). There were no differences between postoperative maternal pain scores and LATCH scores between the two groups. No complications occurred after surgery.Conclusion: The surgical treatment of ankyloglossia by monopolar cautery has a significantly lower incidence of intra-operative bleeding compared to conventional surgery, shorter operative time, and safety. There were no differences in postoperative maternal pain score and LATCH score between the two groups.