National surveys have pointed to a particularly high risk of pediatric overweight among U.S. Hispanics. However, the data have been primarily from the Mexican-American community. We studied the prevalence of overweight and clinical comorbidities in children and youth of predominantly El Salvadoran ancestry. A sample of 309 Hispanic youth, 6-18 years was surveyed from two inner city Washington, DC, clinics. BMI; triceps skinfold (TSF) and subscapular skinfold thickness (SSSF); bioelectrical impedance analysis (BIA); and blood pressure measures were obtained, along with information regarding physical activity, sedentary behavior, dietary history, family, and personal medical history. Thirty-eight percent were overweight (BMI > or = 95th percentile) and 22% at risk for overweight (BMI 85-94th percentile). Thirty-four percent had TSF > or = 90th percentile and 29% had SSSF > or = 90th percentile. Fifty-one percent of males and 70% of females had body fat > 30%. Compared to their nonoverweight counterparts, overweight youth had significantly higher systolic blood pressure (111.4 +/- 1.3 vs. 104.5 +/- 0.9 mm Hg, p < 0.0001). Among children younger than 11 years, overweight was associated with onset of adrenarche (23% vs. 10%, p = 0.01). Participation in one or more sports teams was negatively correlated with overweight) p = 0.04). The prevalence of overweight and at risk for overweight in this sample was twice the national average for U.S. children and 1.7 times greater than that of Mexican-American children in national surveys. Overweight was associated with advanced pubertal development, high body fat, elevated blood pressure, and decreased sports participation.