Metaiodobenzylguanidine (MIBG), a noradrenaline analogue,labelled with radioactive iodine I-123 is used for assessing pre-synaptic activity of the myocardial adrenergic system. The paper describes the mechanism of myocardial I-123-MIBG uptake and the relevant examination methods. It also refers to the necessity of standardising acquisition methods and assessment criteria in order to improve comparability of results, especially numerical results, originating from various countries and centres.Although first introduced as a cardiological diagnostic procedure 30 years ago, I-123-MIBG myocardial scintigraphy continues to be mostly applied as a research method, even though its diagnostic and/or prognostic importance, especially in the case of heart failure, has been widely reported. The recently published results of two extensive retrospective works and a major prospective,multi-centre international ADMIRE-HF study confirmed that I-123-MIBG scintigraphy has a high independent prognostic value in evaluating patients with heart failure. Abnormal myocardial I-123-MIBG uptake can also be indicative of higher risk of ventricular arrhythmias and sudden cardiac death inpatients with heart failure. I-123-MIBG myocardial scintigraphy also seems to have considerable potential for the detection and differentiation of neurodegenerative diseases.