The authors report on a cooperative study of 43 cases of bacterial pericarditis observed in children. This disorder was suspected in patients with septicemia who developed symptoms and signs of pericarditis (precordial pain, muffled heart sounds, pericardial friction rub, cardiomegaly). Early diagnosis of this condition is now facilitated by echocardiography. A combination of medical and surgical treatments (appropriate antibiotic therapy after culture and sensitivity tests and early pericardial drainage) led to complete recovery in almost all of the cases (42 of 43). After long-term follow-up, no cases of constrictive pericarditis were observed.