BACKGROUND: in-hospital life-threatening ventricular arrhythmias (LT-VA) may complicate the course of cardiovascular patients. We aimed to assess the incidence, circumstances, determinants, and outcome of in-hospital LT-VA in order to help clinicians in prescribing appropriate levels of monitoring. METHODS: the study population consisted of all 10,741 consecutive patients (65 ± 15 years, 67.7% males) admitted to a cardiology department in 2009-2014. Terminally ill patients and those with primary arrhythmia diagnosis were excluded. The composite end-point included sudden arrhythmic death, ventricular fibrillation, unstable ventricular tachycardia and appropriate ICD shock unrelated to invasive interventions. RESULTS: the incidence of LT-VA was 0.6%, with no differences regarding age, gender and primary diagnosis of coronary artery disease between patients with and without LT-VA. The incidence of LT-VA was significantly higher (1.2% versus 0.1%, p