Adenotonsillectomy is one of the most common surgical procedures in Germany and the most critical postoperative complication is postoperative hemorrhage, particularly for children. The medical history has been considered superior to laboratory tests. In a retrospective anonymous examination over a 4-year period the data of children subject were recorded. Based on the preoperative questionnaire of the blood coagulation history and the laboratory screening, risk factors for hemorrhage as well as for von-Willebrand-Disease (VWD) were identified. Included in the examination were 171 male and 137 female patients. Postoperative hemorrhage occurred in 43 children (14 %) between the 1st and 13th day after surgery. Children with frequent epistaxis had a significant higher risk of postoperative hemorrhage. A preoperatively pathological hemoglobin value was associated with a significantly higher rate of postoperative bleeding. In children with VWD, a significantly increased risk of postoperative hemorrhage was observed, particularly in male VWD patients. In case of a conspicious family history, especially of the mother in the bleeding questionnaire, a significantly increased risk for VWD could be observed. Here it is advisable to determine the PTT as well as PFA-100 and, to continue with a further VWD step-diagnostics. A suspect preoperative laboratory screening, especially hemoglobin value, is associated with higher risk of postoperative hemorrhage.