BACKGROUND: Post-tonsillectomy hemorrhage (PTH) affects around 4% of patients after tonsillectomy. We hypothesized that preoperative thromboelastography (TEG) might identify patients at higher risk of PTH. OBJECTIVE: Investigate whether evaluation of coagulation function by preoperative TEG might help to predict PTH after tonsillectomy by coblation tonsillectomy (TE). DESIGN: Post-hoc analysis of randomized controlled study. SETTING: Otolaryngology Department between January 2017 and August 2019. PATIENTS AND METHODS: This post-hoc analysis included adults who underwent coblation TE for benign tonsillar disorders. Routine blood tests and TEG were performed preoperatively. The TEG parameters evaluated included coagulation reaction time (R) and maximum thrombus amplitude (MA). MAIN OUTCOME MEASURES: The main outcome was PTH during the 4-week postoperative period. SAMPLE SIZE AND CHARACTERISTICS: 284 RESULTS: The 19 patients (6.7%) that experienced PTH had a higher prevalence of diabetes mellitus, lower use of intraoperative suturing, fewer patients with grade I and II tonsillar enlargement, a higher white blood cell count, lower platelet count, lower fibrinogen level, lower R value, and a lower MA value than patients without PTH (all P