Auscultations acquired from children patients (27 patients, 10.23.9 years, 35.720.8 kg, 132.325.5 cm), were automatically segmented into their components first (S1) and second (S2) heart sounds. A set of time, frequency, and wavelet based features, were extracted from the S2, and analyzed in relation to the noninvasive cuff-based measures of blood pressure (mean blood pressure of 788.8 mmHg). A multivariate regression analysis was performed to determine which features better related to the blood pressure measurements. The best results, in the leave-one-out evaluation, were obtained using the frequency features set (MAE 6.08 mmHg, MAPE 7.85%, ME 0.31 mmHg).