Background. It has been standard teaching in cardiac surgery that drainage of the mediastinum following cardiac surgical procedures is best accomplished using rigid large-bore chest tubes. Recent trends in cardiac surgery have suggested less invasive approaches to a variety of diseases. Difficult drainage problems in the field of general surgery including hepatic and pancreatic collections have been drained successfully with smaller flexible drains for many years. Additionally, many difficult to reach collections in the chest have been drained by invasive radiologists using small pigtail catheters. Methods. We have introduced drainage of the mediastinum using 10-mm flexible, flat, fluted Blake drains. To date, we have used these drains in more than 100 cardiac operations including coronary artery bypass grafting, valve repair/replacements, combined coronary artery bypass grafting/valve operations, heart transplants, septal defects, and mediastinal tumors. Results. We have demonstrated that this form of drainage is as good as using large-bore chest tubes with no significant risk of bleeding or tamponade. Additionally, use of these tubes is less painful, allows more mobility, and earlier discharge with functioning drains in place if necessary. Conclusions. Larger chest tubes are not necessarily better when it comes to draining the mediastinum. The actual area of ingress through the sideholes is considerably less than the surface area provided by the fluted Blake drain. We believe that this system can replace standard chest tubes. (Ann Thorac Surg 2000;70:1109-10) (C) 2000 by The Society of Thoracic Surgeons.