The aim of this study was to determine the outcome of patients who had a chest resternotomy and to identify risk factors for higher in-hospital mortality after re-exploration for bleeding and/or tamponade after cardiac operations. We present our experience of an acceptably low re-exploration rate after cardiac surgery, and the outcomes of those re-explored. This was a retrospective analysis of medical records of all patients who had a chest re-exploration for the control of bleeding and cardiac tamponade over a 7-year period (2000-06), at the Cardiothoracic Centre of the Hospital České Budějovice, Czech Republic. Between 2000 and 2006, 152 patients (3.4% of the total heart operations) underwent re-exploration after heart surgery. One hundred and seven (70.4%) were re-explored for bleeding, 36 (23.7%) for possible tamponade and nine (5.9%) for both. An identifiable source of bleeding was found in 72.4% patients. Risk factors associated with higher in-hospital mortality after re-exploration for bleeding and tamponade include delayed resternotomy, higher levels of lactate and lower levels of haematocrit before revision and other well-known risk factors such as older age, more complex cardiac procedures, redo operations, longer cardiopulmonary bypass, renal failure and diabetes mellitus. Patients who need re-exploration are at a higher risk of complications, morbidity and mortality if the time until re-exploration is prolonged.