OBJECTIVE Air leak is a well-known problem, often leading to great discomfort and prolonged hospitalization. Many methods have been proposed for the prevention or treatment of prolonged air leak, but none of them turned out to offer the perfect solution. The purpose of this study was to evaluate the results of blood pleurodesis in patients with persistent air leak. METHODS From February 2005 through March 2007, 20 patients (14 male and 6 female) ranging in age from 41 to 81 years underwent blood pleurodesis in our department due to persistent air leak (> 7 days). In the majority of patients the underlying disease was emphysema (n = 14). Lobectomy was performed in 10 cases, LVRS in 4 and 3 patients suffered from secondary pneumothorax. Autologous blood pleurodesis was performed at bedside. With apical chest tube placement and an expanded lung, 60 ml of blood was taken from the femoral vein and instilled into the thoracic cavity. Because of the high air leakage the drainage was not clamped but was positioned over the patient to prevent blood running out of the pleural space, but allowing air to be evacuated. Patients were asked to rotate in bed every 15 minutes over a period of 6 hours. The tube was removed 12 h after cessation of the air leak. RESULTS In 14 patients (70 %) closure of the fistula was achieved in less than 12 hours, in 3 within 24 h, in 2 within 48 h, while one patient with LVRS and NSCLC needed reoperation. Only in 2 cases was a second instillation of blood performed. Over a 2- to 24-month follow-up period neither complications nor recurrences were observed. CONCLUSIONS The injection of autologous blood into the pleural space through an existing chest tube is an easy-to-perform, painless and inexpensive method with a high success rate.