An anaesthetised dog preparation was used to examine the pharmacological profiles of xamoterol, cicloprolol, prenalterol and pindolol. The effects of these agents on heart rate and hind limb perfusion pressure revealed that xamoterol is highly cardioselective and has no significant agonist activity at beta 2-receptors and no membrane stabilising effect. These pharmacological properties are not complicated by the formation of active metabolites and may explain the clinical benefits in the long-term treatment of heart failure.