The purpose of this study was to observe the relationship of dietary factors to blood pressure in 5th and 6th grade school children. Salt threshold, salt preference and nutrition knowlege about blood pressure were tested. Twenty-four hour urines were collected for the measurements of the volume and concentrations of sodium, potassium, chloride, calcium, phosphorus, creatinine and urea nitrogen. 1) Mean systolic and diastolic blood pressure of elementary school children were 106.8/67.6mmHg in males and 108.7/69.5mmHg in females. Seven children(4%) of total subjects were found to be hypertensive. Their mean blood pressure was 130.0/86.4mmHg. 2) Urinary excretions of creatinine and urea nitrogen during twenty-four hours were 621.1mg and 1524mg, respectively. The mean daily urinary sodium excretion was 2940mg, which is equivalent to 7.37g NaCl. 3) The daily urinary excretions of other minerals were as follows; potassium was 1301mg, chloride, 4991mg, calcium, 55.7mg and phosphorus, 700.03mg. 4) Salt preference of hypertensive children90.473$pm$0.275) was significantly higher than those of normotensive children(0.473$pm$0.213%), but salt threshold was lower in hypertensives(0.105$pm$0.04%) than normotensives(0.081$pm$0.022%) (p<0.05). INdices for assessing obesity, such as body weight, triceps skinfold, weight for heigth and body surface area, were high in hypertensive children than normotensive children(p<0.05). But there was no significant difference in energy and nutrient intakes between two groups. 5) Various anthropometric measurements had positive correlations with blood pressure, but body muscle mass(%) had a negative correlation with blood pressure. And daily energy and nutrient intakes were not related to blood pressure. 6) Blood pressures-both systolic and diastolic-were significantly correlated with urinary excretions of potassium and chloride. Daily sodium excretion was related to systolic blood pressure, but no related to diastolci blood pressure. There was no relationship of salt threshold to salt preference, and neither threshold nor preference was related to blood pressure. Results of this study suggest that nutrition education program for children including the information about desirable food habits for the prevention of hypertension should be developed.