Various beta-adrenergic receptor antagonists have different effects on myocardial function. A clinical study was performed in 30 patients with symptomatic coronary artery disease and systemic hypertension to compare the effects of single intravenous doses of 0.15 mg/kg celiprolol (n = 16) (third generation beta-blocking agent) and metoprolol (n = 14) (second generation) on left ventricular diastolic function. Parameters derived from pressure, volume, flow, time intervals and their combination were used to characterise diastolic function. After celiprolol administration, parameters of diastolic myocardial function improve (dp/dtip-; relaxation time constant T1, peak filling rate PFR; first-third filling rate FF1/3 or diastolic wall stress-time integral Sigdiasc) or remain unchanged. In contrast, after metoprolol administration parameters of diastolic function seem to be deteriorated (dp/dtip-, T1; Sigdiasc). This indicates an improvement in myocardial relaxation and filling under the influence of celiprolol but not under metoprolol. The left shift of the pressure-volume loops after celiprolol (n = 13), in contrast to metoprolol, supports this interpretation. Celiprolol did not show any deterioration of diastolic function in patients with coronary heart disease and arterial hypertension under these acute conditions.