Objective. To determine if the decision to treat uncomplicated mild hypertension with drugs, in accordance with the WHO/ISH guidelines based on a series of blood pressure (BP) measurements over six months, resulted in the treatment of patients at high risk, on the basis of echocardiography. Background. The value of echocardiography in mild hypertension management remains is unclear. Methods. One hundred and eighteen patients with mild hypertension (90 to 105 mmHg diastolic BP and/or 140 to 180 mmHg systolic BP) were examined by echocardiography at inclusion and followed up for 6 months by a single physician unawere of the echographic results. Results. Drug treatment was given to 48 patients, and 70 remained untreated. Treated patients had higher echographic indices than untreated patients (all p < 0.05): LV mass/body surface area (82.8 +/- 15.9 vs 74.7 +/- 15.0 g/m2), interventricular septal thickness (9.7 +/- 1.7 vs 8.5 +/- 1.3 mm), LV posterior wall thickness (8.4 +/- 1.1 vs 7.8 +/- 1.1 mm), relative wall thickness (0.37 +/- 0.06 vs 0.34 +/- 0.06). Left ventricular (LV) geometry was normal in 98 patients, and 20 had LV concentric remodeling. The 10-year coronary disease risk (Framingham equation) was higher in treated patients than in untreated patients (10.0% vs 6.3%; p < 0.002), and in the 20 patients with concentric remodeling than in those with normal LV geometry (10.4%) vs 4.2%; p < 0.005). Nine of these 20 patients were still untreated at the end of the six-month follow-up period. Conclusion. Rigorous application of the WHO-ISM clinical guidelines in a group of mild hypertensive patients, led to the treatment of patients with slightly higher LV mass and more concentric LV geometry than were found in those not treated. However, a high-risk subgroup, with concentric remodeling, was not identified and left untreated.