Atenolol, a selective beta(1)-adrenergic antagonist, is commonly used to treat hypertension, ischemic heart disease and cardiac dysrhythmias. Few cases of severe atenolol intoxication have been described, and only one of these reports discussed the use of calcium chloride as a treatment. We present a case of atenolol overdose associated with shock and first-degree heart block, in which administration of calcium chloride led to dramatic improvement after failure of conventional treatment. In addition, we discuss the pharmacokinetics, toxicology and management of beta-blocker overdose, focusing on the possible role of calcium chloride.