Background. The role of endogenous relaxin on hypertensive cardiovascular damage remains unknown. We investigated the relaxin level and its relation to cardiovascular function in patients with never treated hypertension (HT). Methods. We studied 42 (47.810 years) never treated patients with HT and 40 age-matched (478.6 years) normotensive individuals. Serum relaxin levels were determined in all subjects using enzyme-linked immunosorbent assay. Left ventricular (LV) diameters were evaluated by transthoracic echocardiography. Ejection fraction and LV mass index were measured. Diastolic functions were evaluated with both conventional and tissue Doppler echocardiography. We evaluated central aortic pressures, heart rate-corrected augmentation index (AIx@75), a marker of wave reflections, and aortic pulse wave velocity (PWV) as indices of elastic-type aortic stiffness of the study population using applanation tonometry (SphygmoCor). Results. Relaxin levels were significantly lower in hypertensive patients as compared with controls (36.57.3 vs 49.739.8 pg/ml, p=0.03). The relaxin level was negatively correlated with brachial and central aortic pressure. However, serum relaxin was not significantly associated with LV diameters, ejection fraction, LV mass index, LV diastolic function, AIx@75 or aortic PWV in our study. Conclusion. Serum relaxin is decreased in patients with HT. However, low endogenous relaxin is not related to cardiovascular function.