To evaluate the efficacy of Floseal as a hemostatic sealant compared to traditional electrocautery hemostasis after cold knife adenotonsillectomy. Prospective, randomized, controlled trial of 68 consecutive patients undergoing cold steel adenotonsillectomy. Patients were randomized to receive either Floseal (FS) or electrocautery (EC) for hemostasis. FS patients had shorter operative times than EC patients (16 min vs 31.2 min, P < 0.0001) and less blood loss (49.2 mL vs 70.8 mL, P < 0.05). Four EC patients were crossed over to Floseal when adequate hemostasis could not be achieved in the adenoid bed. No Floseal patients were crossed over. FS patients had significantly less pain on postoperative days two through 11 (P < 0.05) and less use of narcotic pain medications over the first 10 postoperative days (P < 0.05). FS patients also had a faster return to regular diet (5.5 days vs 7.9 days, P < 0.01) and activity (5.3 days vs 7.8 days, P < 0.01) as compared to the EC patients. There were no significant complications in either group. Floseal is safe and efficacious, and decreases postoperative morbidity as compared to electrocautery hemostasis after cold steel adenotonsillectomy. This study demonstrates the safety and efficacy of Floseal as a hemostatic method in children undergoing adenotonsillectomy.