A 59-year-old man with history of diabetes mellitus presented to the emergency department with chest discomfort and pain. On admission, electrocardiogram revealed low voltage and ST-segment elevation (II, II aVF). Chest x-ray showed marked cardiomegaly. Laboratory test revealed leukocytosis (23.12 x10^9/L), elevated serum C-reactive protein (CRP): 16.84 mg/dL). The cardiac markers (CK-MB, TnI) were normal range but pro-BNP was elevated (9263.8 pg/mL). Echocardiogram showed rupture of the left ventricular apex with larged pericaridial effusion (Fig.1). Chest computed tomography revealed large left ventricular aneurysm with rupture in the anteroinferior wall and associated hemopericardium (Fig.2). The patient underwent emergency cardiac surgery. There was large amount of prulent pericardial effusion and detection of Streptococcus pneumoniae in culture of pericardial effusion. It was successfully repaired surgically and the patient received antibiotics management. Patient``s symptom was improved and the patient made a good recovery. We report uncommon case of left ventricular free wall rupture caused by Streptococcus pneumonia pericarditis.