Episodes of worsening symptoms and signs characterize the clinical course of patients with chronic heart failure (HF). These events are associated with poorer quality of life, increased risks of hospitalization and death and are a major burden on healthcare resources. They usually require diuretic therapy, either administered intravenously or by escalation of oral doses or with combinations of different diuretic classes. Additional treatments may also have a major role, including initiation of guideline-recommended medical therapy (GRMT). Hospital admission is often necessary but treatment in the emergency service or in outpatient clinics or by primary care physicians has become increasingly used. Prevention of first and recurring episodes of worsening HF is an essential component of HF treatment and this may be achieved through early and rapid administration of GRMT. The aim of the present clinical consensus statement by the Heart Failure Association of the European Society of Cardiology is to provide an update on the definition, clinical characteristics, management and prevention of worsening HF in clinical practice.