Injury of the heart with concomitant pericardial tamponade as a result of sternal bone marrow biopsy is rare. An 80-year-old man was admitted with dehydration and non-specified abdominal pain to the regional hospital. Sternal aspiration biopsy was performed because of anemia and thrombocytopenia. Later on, because of the back pain, general weakness and blood pressure drop, an echocardiography examination was indicated. Pericardial fluid collection was found. Anticipated ascending aortic dissection was excluded on computed tomography scan, but pericardial fluid collection was confirmed. Transfer to our cardiac surgical facility ensued. Limited heart tamponade was affirmed on echocardiography and surgery was immediately indicated. Blood effusion was found in upper mediastinal fat tissue and 300 mL of blood were evacuated from opened pericardial space. Stab wound by sternal biopsy needle at the upper part of ascending aorta was repaired by pledgeted suture. Postoperative course was uneventful.