The objective of this study was to assess the effect of weight loss on sleep-disordered breathing (SDB) in obese teenagers attending a residential treatment center. We also assessed whether the presence of SDB at the start of the weight management therapy was correlated with the amount of weight loss achieved. Obese teenagers were recruited and underwent anthropometry and sleep screening. Subjects with SDB (apnea hypopnea index (AHI)>or=2) received a follow-up screening after weight loss therapy. Sixty-one obese subjects were included (age=14.8+/-2.3; BMI z score=2.7+/-0.4). Thirty-one subjects were diagnosed with SDB with 38% continuing to have residual SDB after a median weight loss of 24.0 kg. Subjects with SDB had a higher median relative decrease in BMI z score compared to subjects without SDB which was 30.5, 33.6, and 50.4% in the group with AHI of the baseline screening study<2, 2<or=AHI<5, and AHI>or=5, respectively (P=0.02). AHI of the baseline screening study correlated significantly with the relative decrease in BMI z score (partial r=0.37; P=0.003), controlling for gender, age, initial BMI z score, and time between both studies. In conclusion, weight loss was successful in treating SDB in obese teenagers. In addition, there was a positive association between the severity of SDB at the start of the treatment and the amount of weight loss achieved. These findings are in favor of considering weight loss as a first-line treatment for SDB in obese children and adolescents.