The aim of this study was to clarify the relation among systolic blood pressure (SBP), serum insulin, leptin, visceral fat accumulation and family history of hypertension, and to elucidate the pathophysiologic mechanism of blood pressure elevation in obese children. This study examined 109 obese children with a family history of hypertension (OF: 77 boys and 32 girls), and 83 obese children without such a history (ON: 60 boys and 23 girls). Body height and weight, and percent of body fat were measured and the percent of relative weight was calculated. Both boys and girls, the two groups were matched with respect to age, height, and weight. SBP was measured in the seated position using an automated recorder. Abdominal fat thickness (maximum preperitoneal fat thickness: Pmax; minimum subcutaneous fat thickness: Smin) were measured using ultrasonography. The fasting serum levels of insulin and leptin were measured by radioimmunoassay. All subjects were simply obese, without diabetic states. In both OF and ON, SBP was associated with insulin levels, leptin levels, and Pmax by simple regression analysis, and with insulin levels by stepwise regression analysis. Insulin levels were associated with leptin levels and Pmax by simple regression analysis, and with leptin levels by stepwise regression analysis. These findings indicated that SBP was associated with hyperinsulinemia, hyperleptinemia and visceral accumulation regardless of a family history of hypertension in obese children, as well as later in adult obesity. For primary prevention of hypertension, these results support the importance of implementation of a strategy to prevent obesity, especially visceral obesity. An effective strategy for preventing childhood obesity will contribute to a future decrement in cases of metabolic syndrome, including adulthood hypertension.