Late arterial hypertension has been identified as a major predictor for morbidity and mortality in aortic coarctation (AoC) patients. Few data are available about efficacy and tolerability of angiotensin converting enzyme inhibitors vs beta-blockers in young AoC patients. This study aimed to evaluate the tolerability and efficacy on 24-h blood pressure (BP) and left ventricular mass/height(2.7) (LVMI), of atenolol vs enalapril. We enrolled consecutive AoC hypertensive patients with (a) no history of BP treatment or after 448 h of withdrawn, (b) aged 6-20 years, (c) body mass index (BMI) < 90th percentile for age and sex, (d) 412 months from a successful AoC repair and (e) no major associated cardiovascular abnormalities. All patient were evaluated with 24-h ambulatory BP monitoring, standard echocardiography, strain-strain rate imaging, at enrolment, 3, 6 and 12 months of treatment. We studied 51 AoC patients (13 +/- 3.9 years, BMI: 21.4 +/- 4.3 kgm(-2)). Patients were randomly assigned at atenolol treatment (n = 26), or enalapril treatment (n = 25). The mean follow-up duration was 11 +/- 2 months. Both drugs were able to significantly reduce 24-systolic BP (SBP; atenolol: 133 +/- 11 mm Hg vs 124 +/- 16 mm Hg, P = 0.016; enalapril: 135 +/- 6 mm Hg vs 127 +/- 7 mm Hg, P = 0.001). Only enalapril was able to significantly reduce LVMI (47 +/- 12 vs 39.6 +/- 10 gm(-2.7), P = 0.016). Only in atenolol group in two cases (7.7%) drug withdrawal was needed because of adverse events. Enalapril and atenolol are similarly effective in reducing SBP. However, only enalapril demonstrated a significant reduction of LVMI. In no case, enalapril was stopped because of adverse events.