Objective: The aim of this study was to assess the adequacy of our treatment strategy for patients with post-sternotomy mediastinitis. Methods: Between May 1997 and December 2000, 1,045 consecutive adult cardiac operations were performed at our center. Mediastinitis occurred in 8 patients (0.77%) and as treatment, they underwent (1) aggressive debridement, (2) closed irrigation and drainage, and (3) transvenous administration of antibiotics. We irrigated the mediastinum with 0.1–1.0% povidone-iodine solution, alternating with electrolyzed strong acid aqueous solution. We subsequently reviewed the outcome after the closed irrigation treatment for patients with post-sternotomy mediastinitis. Results: In four of the 8 patients, the culture specimen grew Methicillin-resistant Staphylococcus aureus. In the others, Serratia marcescens, Staphylococcus epidermidis, Pseudomonas aeruginosa and Gram-negative rods were cultured. The mean period between primary surgery and the diagnosis of mediastinitis was 16.3 (8–57) days. The mean period between diagnosis of mediastinitis and the start of the irrigation treatment was 0.8 (0–3) days. The mean irrigation period was 30.0 (14–17) days. The irrigation complications were mild hepatic dysfunction in 2 patients, hyponatremia in 2 and protracted wound infection in 1. The hospital mortality was 1/8 (12.5%). Seven survivors are free from recurrent mediastinitis. Conclusions: Our experience of closed irrigation and drainage suggests that it can yield satisfactory results after poststernotomy mediastinitis, comparable to other reported results with or without muscle flaps.