Introduction: Quality assurance in health care involves the evaluation of outcomes, cost-benefit ratios, and access to the delivery system. This literature review was undertaken to clarify the incidence of serious posttonsillectomy complications to better understand the outcome component of quality assurance. Material and Methods: A Medline review was undertaken using the key word ‘tonsillectomy' AND each of the following: ‘serious', ‘complications' and ‘review'; ‘meta-analysis', ‘Cochrane'; ‘life-threatening', ‘death' and ‘disability'. Results: 454 articles were identified with the following search items in combination with ‘tonsillectomy': ‘serious' (154), ‘complications', ‘review' (24), ‘meta-analysis' (38), ‘Cochrane' (43), ‘life-threatening' (87), ‘death' (91), ‘disability' (17). Sixty-seven articles described a complication rate and were therefore eligible for review: 22 case reports, 9 case series, 2 questionnaires and 33 studies with a more or less precise complication rate were obtainable. Most articles (n = 30) reported the rate of posttonsillectomy hemorrhage with a considerable range. Fifteen articles reported the incidence of death, which ranged from 1:7,132 to 1:170,000 and almost always resulted from excessive hemorrhage. All other complications were mentioned in case reports. Conclusion: The most common postoperative complication of tonsillectomy is bleeding. However, the incidence varies considerably across studies depending on the study design, follow-up and definition of postoperative bleeding. Other serious adverse events, such as neurological disabilities, emphysema (with or without pneumomediastinum), or vascular problems outside the neck are infrequent.