Non-glutaraldehyde fixation of an organ or a prosthesis for implantation ina mammal is based upon carbodiimide treatment. A solution containing a sterilizingagent, such as EDC, in combination with a coupling enhancer, such as Sulfo-NHS,and a high concentration of a diamine cross linking agent is used. As a result,only minimal surface reduction occurs during fixation, and the resultant productsshow a dramatic increase in resistance to calcification.