The results of an extensive pre-clinical and clinical research programme indicate that celiprolol is a safe and effective treatment for both hypertension and angina pectoris. Celiprolol is well absorbed, is largely unmetabolized, and is excreted equally in the urine and bile. As a result of this pharmacokinetic profile celiprolol can be safely administered to the elderly and to patients with renal or hepatic impairment. Haemodynamic studies indicate that celiprolol lowers arterial blood pressure, and decreases both renal vascular resistance and peripheral vascular resistance. Celiprolol does not depress myocardial function, neither does it induce bronchoconstriction in asthmatic patients. Weak alpha 2-adrenoceptor antagonism, combined with beta 2-adrenoceptor agonism are thought to contribute to these properties. The antihypertensive efficacy of celiprolol, 200 mg/day, is comparable to that of propranolol, atenolol and nadolol. Moreover, the actions of celiprolol last for 24 h, and are accompanied by less resting bradycardia than that seen with other beta-blockers. The anti-anginal efficacy of celiprolol is similar to that of atenolol, propranolol and metoprolol. In addition, celiprolol decreases the ventricular rate in patients with atrial tachyarrhythmias. This effect results from its ability to slow atrioventricular conduction. Celiprolol is generally very well tolerated.