OBJECTIVE Protein-energy malnutrition remains a major public health problem in many countries. Scanty information is available about the effects of malnutrition during childhood on blood pressure (BP). METHODS In a cross-sectional study we assessed the BP of 172 children older than 2 years living in shantytowns in São Paulo city. Ninety-one children were malnourished (height-for-age or weight-for-age Z-score below -1 of the NCHS references); 20 had recovered from malnutrition after an average time of 6.4 years, and 61 were non-malnourished controls. RESULTS A greater percentage of children in the malnourished and recovered groups had increased systolic or diastolic BP (>95th percentile of the Update of the 2nd Task Force references) after adjusting for age, sex and height, compared to the controls (29, 20 and 2%, respectively, p < 0.001). Mean diastolic BP, adjusted for age, sex, race, weight, height and birth weight, was significantly increased in malnourished and recovered children compared to controls (65.2 +/- 0.6, 66.5 +/- 1.5, and 61.8 +/- 0.8 mm Hg, respectively, p < 0.01). CONCLUSIONS BP is increased in malnourished children and in those who recovered from malnutrition after an average period of 6 years. Malnutrition occurring during childhood may represent a risk factor for increased BP later in life.