Introduction: Postoperative bleeding is a common and potentially fatal complication following open heart surgery, studies reporting a reoperation rate for bleeding in the range of 2-6%. Surgical outcome after such reoperations has not been previously studied in Iceland. Material and methods: In this retrospective study were included all adults that underwent open heart surgery in Iceland during a 6 year period, between January 1, 2000 and December 31, 2005. Results: There were 103 reoperations (mean age 68 years, 76% males), but throughout the same 6 year period a total of 1295 open heart procedures were performed, the reoperation-rate being 8%. One third of all patients were on aspirin and 8% on clopidogrel less than 5 days before surgery. The bleeding in the primary operation averaged 1523 ml (range 300-4780) and 3942 ml for the first 24 hours postoperatively. Half of the patients were reoperated on within 2 h and 97% within 24 hours. The patients received on average 16.5 units of packed cells, 15.6 units of plasma and 2.3 sets of thrombocytes. The most common postoperative complication was atrial fibrillation (58.3%), pleural effusion that needed chest tube drainage (24.3%), myocardial infarction (23.3%) and sternal wound infection (11.7%). Median length of stay was 14 days (range 6-85), including 2 days (range 1-38) in ICU. Operative mortality was 15.5% and 1 year crude survival 79.6%. Conclusion: Reoperation-rate for bleeding was 8%, which is higher compared to other studies. Bleeding is a serious complication following open heart surgery with high morbidity and significant mortality. Key words: Postoperative bleeding, reoperation, open heart surgery, CABG, valve replacement, complications, transfusions, survival. Correspondence: Tomas Gudbjartsson, email@example.com.