Objective To analyze patients’ return to normal activity, pain scores, narcotic use, and adverse events after undergoing tonsillectomy or adenotonsillectomy with monopolar electrocautery or radiofrequency ablation. Study Design Randomized double-blinded clinical trial based on prospective parallel design. Setting Academic medical center and tertiary children’s hospital between March 2018 and July 2019. Methods Inclusion criteria included patients aged ≥3 years with surgical indication of recurrent tonsillitis or airway obstruction/sleep-disordered breathing. Patients were randomly assigned to monopolar electrocautery or radiofrequency ablation. Patients were blinded to treatment assignment. Survey questions answered via text or email were collected daily until postoperative day 15. The primary outcome was the patient’s return to normal activity. Secondary outcomes included daily pain score, total amount of postoperative narcotic use, and adverse events. Results Of the 236 patients who met inclusion criteria and were randomly assigned to radiofrequency ablation or monopolar electrocautery, 230 completed the study (radiofrequency ablation, n = 112; monopolar electrocautery, n = 118). There was no statistically significant difference between the groups in the number of days for return to normal activity ( P = .89), daily pain scores over 15 postoperative days ( P = .46), postoperative narcotic use ( P = .61), or return to hospital for any reason ( P = .60), including bleeding as an adverse event ( P = .13). Conclusions As one of the largest randomized controlled trials examining instrumentation in tonsillectomy, our data do not show a difference between monopolar electrocautery and radiofrequency ablation with regard to return to normal activity, daily pain scores, total postoperative narcotic use, or adverse events.