Background and Significance: Tonsillectomy is the most common major surgical procedure performed on children in the United States with nearly 300,000 procedures performed each year, primarily for the indication of obstructive sleep disordered breathing (OSDB). Conventional (total) tonsillectomy removes the tonsillar capsule, and partial tonsillectomy preserves the capsule by shaving away the tonsils using an endoscopic microdebrider. Partial tonsillectomy results in less pain, fewer days to normal activity and diet, and fewer days of analgesics than total tonsillectomy. There are no significant differences between the techniques in blood loss or postoperative life improved Historical evidence suggests that eventually there will be tonsillar regrowth with partial tonsillectomy. However, in a 2003 follow-up report of 243 children undergoing partial tonsillectomy and 107 undergoing complete tonsillectomy from 1998 through 2002 for OSDB there was no evidence of significant tonsillar regrowth. (1) We will follow-up children undergoing partial or complete tonsillectomies at the Cleveland Clinic from 1998 through 2002. There will be standardized tonsillar examinations by two observers, with a third observer in cases of significant disagreement, and questionnaires evaluating sleep apnea and daytime sleepiness, and number of tonsillar infections.