Objective: (1) To evaluate the effect of adenotonsillectomy (T&A) on clinical signs in obese children with obstructive sleep apnea (OSA); (2) to evaluate the changes in tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 levels pre- and post-surgery; and (3) to determine a potential explanation for changes in cytokine levels after T&A therapy. Subjects and methods: In brief, 90 obese children with USA were enrolled. Polysomnographic data, such as an apnea-hypopnea index (AHI) and oxyhemoglobin saturation (SaO(2)), and demographic information, such as body mass index (BMI), were collected. TNF-alpha and IL-6 levels were determined before and 6 months after T&A treatment. Results: It was observed that 61.1% of obese children with USA were persistent after T&A therapy. In general, AHI (events/h) measures decreased from 22.26 +/- 9.141 to 8.88 +/- 5.909 before and after a 6-month follow-up period, respectively, and nadir SaO(2) (%) levels increased from 74.26 +/- 7.486 to 86.37 +/- 5.578 pre- and post-surgery, respectively. However, no discernible differences in BMI measures before and after a 6month follow-up period (40.996 +/- 5.2486 vs. 40.597 +/- 5.0540) were observed. No significant differences in the TNF-alpha and IL-6 levels pre- and post-surgery were observed. TNF-alpha and IL-6 plasma levels were highly correlated with BMI measurements (TNF-alpha: r(2) = 0.2350, P < 0.001; IL-6: r(2) = 0.6629, P < 0.001). In contrast, there was no association between plasma levels and AHI measures (TNF-alpha: r(2) = 0.03377, P = 0.0829; IL-6: r(2) = 0.03946, P = 0.0605). Conclusion: T&A therapy can improve clinical symptoms and signs but is not a cure for the treatment of obese children with USA. The inflammation levels of TNF-alpha and IL-6 changed little. To reduce the risk for excessive daytime sleepiness, supplementary therapies should be introduced for USA. (C) 2013 Published by Elsevier Ireland Ltd.