We compared the effects of 6 months administration of atenolol or nebivolol on resting and exercise hemodynamic parameters and maximal exercise capacity, in 26 patients with hypertension and left ventricular (LV) diastolic dysfunction (ejection fraction >50%, end-diastolic diameter <60 mm and increased pulmonary wedge pressure at rest and/or at peak exercise). Both atenolol and nebivolol administration was associated with a significant decrease in the resting and peak exercise heart rate and blood pressure and in LV mass, with an increase in the E/A ratio. This latter effect was greater with nebivolol. Nebivolol was associated with an increase in the peak VO(2), VO(2) at the anaerobic threshold and with a decrease in the VE/VCO(2) ratio. With regards to the hemodynamic parameters, compared to patients on atenolol, those on nebivolol showed a lower reduction in the cardiac index, a greater increase in the stroke volume index and a decline in the mean pulmonary artery pressure and pulmonary wedge pressure, both at rest and peak exercise. Thus, although the two beta-blockers have a similar antihypertensive action, nebivolol administration was associated with a greater hemodynamic improvement, compared to atenolol.