Children who are referred to ENT clinic because of sleep-disordered breathing and fulfil the inclusion criteria undergo polysomnography (PSG) and fill in questionnaires. Depending on the outcome of the PSG, whether a) the child have mild to moderate OSA (AHI between 2-9.9) the family is asked to be in the study. If yes, the doctor take a sealed envelope and open it, either the child are randomized to adenotonsillectomy (ATE) or 6 months expectancy. Whether PSG shows b) severe OSA and the family accept participation the child is operated within a month. There is a straification beetween 2 groups, if AHI is 1) between 10 and 29.9 or 2) above 30. A sealed envelope is open in the operating room by the surgeon. The child is randomized to either ATE or ATE and suturing of the tonsillar pillars. The study is blinded for the family, who will not know which method the child has undergone. After 6 months all children will undergo follow-up with PSG and questionnaires. If the expectancy group will deteriorate during waiting time, or the child still has moderate to severe OSA, they will undergo ATE. Further follow-ups at three and ten years. Altogether 160 children should be evaluated with two PSG, 80 in each group.