Primary hyperaldosteronism (PHA) is thought to have a harmful effect on the cardiovascular system and, in recent years, the number of cases of hypertension due to PHA has been increasing. The aims of this study were to determine the prevalence of PHA and to assess cardiac damage associated with the condition in 183 consecutive hypertensive patients. A full secondary hypertension work-up was performed, and included ECG and echocardiography. In total, 11 (6%) patients were diagnosed with PHA. Compared with other hypertensives, those with PHA had higher systolic blood pressure, more frequently had evidence of left ventricular hypertrophy on ECG (45.5% vs 11.6%; P<.01), and had a larger left ventricular mass on echocardiography (145.5 g/m2 vs 97.52 g/m2; P<.0001). In conclusion, PHA is a significant contributor to the increasing prevalence of hypertension and its effect on the heart is greater than that of other causes of hypertension.