Objective Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a common sleep problem. The aim of this study is to investigate the association between OSAHS and blood pressure (BP) in snoring children. Methods Snoring children were recruited from January 2009 to December 2010. Clinical history was taken accompanied by a physical examination and polysomnography were performed. A child with an apnea/hypopnea index (AHI) greater than 5hr1 or obstructive apnea index (OAI) greater than 1hr1 was diagnosed as having OSAHS. Ambulatory BP monitoring was performed for each child. BP load, BP index and nocturnal BP dipping were calculated for each child. Results One hundred forty-five children with snoring were recruited and 107 of them were diagnosed with OSAHS. There were no differences between those with or without OSA in age or gender distribution. The OSAHS children had higher mean nighttime systolic and diastolic BP, increased BP load, and decreased nocturnal BP dipping compared to the non-OSAHS children (SBP: P=0.03, DBP: P<0.001, BP load: P=0.001, SBP dipping: P=0.03, DBP dipping: P=0.04). Multiple regression analysis showed that mean nighttime systolic BP was related to age, obesity, and oxygen desaturation index (ODI) (P=0.04, 0.03, and 0.02 respectively), while mean nighttime diastolic BP was related to obesity and ODI (P=0.03 and 0.04, respectively). Conclusions OSAHS children had a higher nocturnal BP than non-OSAHS children and dysregulation of BP control reflected by decreased nocturnal BP dipping. Frequency of oxygen desaturation, apneas, and obesity were related to BP. Pediatr Pulmonol. 2013; 48:274279. (c) 2012 Wiley Periodicals, Inc.