Secondary Specific Aim. For all children with the original AHI at diagnosis of >2 hrTST, we expect improvements in the severity of sleep apnea to occur following treatment with montelukast. Therefore, we will examine the overall reduction in AHI and also how many of these children have AHI< 2 after the 16-week treatment. In other words, the percentage of children converting from needing T&A surgery before treatment with montelukast to not needing surgery after treatment will be examined.