Background : 6.1% of red blood cells and whole blood issued to the operating room was not transfused to the patients and discarded in Seoul National University Hospital in 1994. Objectives : We planned to set up an effective management program of blood in the operating room and we investigated whether this program could reduce the disposal rate of blood. Methods : We made a guideline of blood management in the operating room through a workshop. The guideline was revised after a preliminary application. The revised guideline was applied for 5 months from May to September in 1996. The disposal rate was compared before and after the installation of the new program. Results : 5,336 units of blood were issued to the operating room for 5 months. Disposal rate of red blood cells and whole blood was markedly reduced from 6.2% in May to 2.1% in September(p<0.05). The average disposal rate was 3.7% during the five months. Conclusion : We were able to reduce the disposal of unused blood in the operating room through the development and the application of a new blood management program.