Systolic and diastolic blood pressures have been evaluated in 645 school children aged 1 to 4 years old. Mercury-gravity manometer was used, and diastolic pressure was assessed taking Korotkoff is fifth phase. Blood pressure with sex, age, body height and body weight was correlated. There was no significant difference of tension values between both sexes. Diastolic blood pressure increased progressively and notoriously for each age interval (12 months) in both sexes. Systolic blood pressure increased notoriously only in the 3 and 4 years girls group. The partial correlation and stepwise regression analyses of variables age, body height and body weight with blood pressure showed that body weight was the only variable significantly related to systolic in both sexes, while body weight and age in boys and none of them in girls with the diastolic.