In a randomized, blind crossover study in 14 hypertensive patients with asthma, involving placebo and chronically administered (3 weeks) equipotent beta1-blocking doses of atenolol 100 mg once daily and metoprolol 100 mg bid, atenolol and metoprolol produced a similar fall in blood pressure. Atenolol caused significantly (p less than 0.05) less bronchospasm in terms of fewer asthmatic attacks, more asthma-free days, less frequent sensations of moderate to very severe, wheeziness and less effect on the evening peak flow rate. It was concluded that, in patients with asthma who require beta blockade, atenolol is the preferred agent, co-prescribed with a beta2 stimulant.