Pericardial effusion is a relatively common clinical condition with a variety of clinical manifestations ranging from incidentally discovered asymptomatic cases to life-threatening cardiac tamponade. The etiology encompasses idiopathic cases and forms secondary to different conditions, including autoimmune diseases, malignancies, metabolic disorders, etc. While medical therapy should be offered to patients with elevation of inflammatory markers, in specific forms treatment should be appropriate to the underlying disorder. In cases with hemodynamic compromise pericardial drainage either with pericardiocentesis or pericardial "window" is indicated for therapeutic and diagnostic purposes. In the remainder, factors like comorbidities, size and location of the pericardial effusion will influence the clinical decision making. In asymptomatic or minimally symptomatic chronic large idiopathic pericardial effusions, according to recent evidence, a conservative approach with watchful waiting seems the most reasonable option. The prognosis of pericardial effusions largely depends on the underlying etiologies. Metastatic spread to the pericardium has an ominous prognosis whereas large to moderate effusions have been often associated with known or newly discovered specific underlying causes. Chronic small idiopathic effusions have an excellent prognosis and do not require specific monitoring. Large chronic idiopathic effusions in clinically stable patients require a 3 to 6-month assessment ideally in a specialized unit.