Xamoterol (ICI 118,587) is a partial agonist of beta1-adrenoceptors. Xamoterol acts on the cardiac beta 1-adrenergic receptor, modifies the response of the heart to variations in sympathetic activity. At rest, it produces modest improvements in cardiac contractility, relaxation, and filling without increase in myocardial oxygen demand. The improvements are maintained during exercise although the attendant tachycardia is attenuated. The beneficial effects of xamoterol on both systolic and diastolic function suggested that it would be effective in patients with mild-to-moderate heart failure, and this was demonstrated in small placebo-controlled studies where effort tolerance and symptoms were improved. Xamoterol produced improvements in exercise capacity, clinical signs, symptoms and quality of life with a low incidence of adverse experiences. Xamoterol is effective as monotherapy in heart failure.