In accordance with the present invention, there is disclosed surgical methods and apparatus for accessing and stabilizing the heart. The methods and apparatus facilitate access to an anastomosis site, allows various instruments or devices to be maneuvered and secured in place, and provide stabilization of the heart. In particular, the apparatus involves a retractor assembly having a pair of opposing blades having a channel adapted to engage an incision in a patient. The retractor blades may have features to cooperatively engage an instrument mount. The instrument mount may hold an instrument, such as a tissue stabilizer, and allows the instrument to be easily maneuvered. The retractor blades may have a number of suture locks for securing sutures used during surgery. The retractor system is particularly useful in accessing, positioning and stabilizing the beating heart for coronary artery bypass graft surgery.