Thoracic electrical bioimpedance is a new non-invasive technique for obtaining haemodynamic parameters. The method involves the passing of low amperage, high frequency current through the thorax. The current induces a change of resistance within the thorax, which is registered by electrodes. The overall impedance of the thorax is a measure of the electrical resistance of the thorax to this high frequency, low amplitude current. In clinical practice, thoracic electrical bioimpedance has been applied in diagnostic, therapeutic, and prognostic use in patients with heart failure and hypertension, patients with pacemakers, within the scope of early diagnosis of implant rejection following heart transplantation, as well as in patients with kidney disorders, before and after dialysis. However, one of its most important applications is in the determination of antihypertensive therapy, because it provides the parameters that reflect the genesis of arterial blood pressure. In assessing these parameters, optimal therapy adjusted to the haemodynamic status of each patient can be prescribed.