CYP17A1 gene encodes the cytochrome P450 enzyme CYP17A1, a key enzyme involved in steroid metabolism. A single nucleotide polymorphism (SNP) near CYP17A1, rs11191548, showed significant association with hypertension in European adults. However, this association has not been demonstrated in children thus far. Additionally, the role of CYP17A1 in elevating blood pressure (BP) is unclear. We investigated the association of rs11191548 with hypertension in Chinese children. A total of 3422 children participated in the study, including 1009 children with elevated BP (EBP, including prehypertension and hypertension) and 2413 children with normal BP. SNP rs11191548 was associated with systolic BP (SBP) (CC vs TT: P=4.8 x 10(-4); additive model: P = 0.002; dominant model: P = 0.011; recessive model: P = 0.001) and EBP (CC vs TT: odds ratio (OR) = 0.43, 95% confidence interval (CI) 0.26-0.72, P = 0.001; additive model: OR = 0.74, 95% CI 0.61-0.90, P = 0.002; dominant model: OR = 0.76, 95% CI 0.60-0.96, P = 0.022; recessive model: recessive model: OR = 0.46, 95% CI 0.28-0.77, P = 0.003) in girls, but there was no statistically significant association between the SNP and diastolic BP in boys or girls. Our results also showed that rs11191548 was more significantly associated with SBP and EBP in obese girls than in girls of normal weight. Our study indicated that the SNP rs11191548, near CYP17A1, was associated with EBP in children. Moreover, we found a sex-specific effect of rs11191548 on SBP in Chinese children. Further studies are necessary to clarify the association between this CYP17A1 polymorphism and BP.