Thirteen patients with successful or unsuccessful delayed sternal closure (DSC) after open heart surgery were reviewed. The indications of DSC were cardiac dilatation in 12 patients and intractable bleeding in one. Patients were divided into two groups as follows: Group A of 7 patients with mediastinum being sealed by prosthetic material, and Group B of 6 patients with primary skin closure by mobilized skin-flap. Postoperative complications and prognosis were compared between these two groups. There were 6 long term survivors. In group A, there were 4 deaths, 2 from low output syndrome (LOS) and 2 from sepsis due to mediastinitis. In group B, 2 died of LOS and 1 died of multiple organ failure, while no patients developed mediastinitis. In patients with unsuccessful DSC, mainly due to poor hemodynamics, there found no tendencies of decrease in CVP and LAP levels and no reduction in the amount of catecholamine dosage prior to attempted DSC. In conclusion, 1) mediastinal isolation with primary skin closure seemed more effective for preventing mediastinitis than coverage with prosthetic materials, 2) DSC was possible when there were hemodynamic improvements with decrease in CVP and LAP levels, and reduction in catecholamine dosage, and 3) plastic surgical technique was useful for primary skin closure.