Despite the otolaryngologist's most diligent efforts to prevent it, hemorrhage is the most common, albeit sporadic, significant complication of tonsillectomy. For this retrospective study of post-tonsillectomy hemorrhage rates, we examined the charts of 430 consecutive tonsillectomy patients who had been operated on by one of two general otolaryngologists at our institution. The two surgeons used the same removal technique (cold dissection and snare), but slightly different methods of hemostasis. We found that the overall bleeding rate was 4%; the primary (< 24 hr) hemorrhage rate was 0.23%, and the secondary rate was 3.7%. Factors that were positively correlated with postoperative bleeding were the patient's sex, the time of year the surgery was performed, the length of the procedure, the amount of blood lost during surgery, and the use of intraoperative vasoconstrictors and steroids. However, we believe the use of steroids can probably be discounted as a causative factor. The chi 2 test was used to determine statistical significance. None of the 21 patients who were operated on for peritonsillar abscess experienced any delayed postoperative bleeding. The mean decrease in hemoglobin was 2.3 grams; the lowest postoperative level was 6.6 grams. The highest incidence of delayed bleeding occurred on the eighth postoperative day. Two patients required transfusions, and both recovered without any adverse consequences. It appears that one controllable variable in preventing delayed bleeding following tonsillectomy and adenoidectomy might be related to certain details of hemostatic technique. Vasoconstrictors and "field" cauterization might be associated with an increased temporal and spatial application of coagulating current. Although this technique is very effective in preventing primary hemorrhage, it does result in a deeper and more extensive zone of necrosis and the exposure of more and larger vessels when sloughing of the eschar occurs.