Abstract Objective: Obesity is considered a pseudo-Cushing state and often elevated levels of cortisol and its metabolites can be found; however, the relationship between cortisol metabolites and blood pressure (BP) in obese children is understudied. 11b-hydroxysteroid dehydrogenase type 2 (11b-HSD-2) catalyses the reversible conversion of physiological glucocorticoids (tetrahydrocortisol, THF and allo-tetrahydrocortisol, allo-THF) to inactive products (tetrahydrocortisone, THE). An increase in the THFs/THE ratio reflects 11b-HSD-2 impairment and has been associated with BP elevation. Ambulatory blood pressure monitoring (ABPM) provides an accurate measurement of BP during 24 hours. We aimed to investigate the relationship between BP measured by ABPM, urinary cortisol and its metabolites, in a sample of obese children. Design and method: 50 obese children aged between 8 and 17 years (mean age 11.5 ± 3.3 years, 66% males), were included in the present study. Children underwent ABPM. Cortisol, sodium, THF, allo-THF and THE were measured on urinary 24-hour collection. Cortisol urinary metabolites were quantified by liquid chromatography tandem mass spectrometry (Nexera Shimadzu, 4500 MD Sciex). Results: The THF + alloTHF/THE ratio negatively correlates with 24-hours urinary sodium excretion (p = -0.346; r = 0.015) and to SBP and DBP load (% of measure of PAS > 130mmHg or % of PAD > 80mmHg) (respectively r = 0.283 p = 0.047 and r = 0,284; p = 0.046). No correlation between THFs/THE ratio and daytime or nighttime SPB or DBP were found. The sum of urinary cortisol and its metabolites, a gross index of relative excess of cortisol, is directly correlated with SBP load (r = 0.355; p = 0.029). Conclusions: In our sample of obese children, both the impaired activity of the 11b-HSD-2 and the amount of cortisol and its metabolites excreted by urine are associated with an excessive 24-h BP load. Reduced urinary sodium excretion mediated by increasing of THF/THE ratio could be involved.